Implemented DataAnnotation based validation for Tapeti messages

Fixed class name missing when selecting from Tapeti class
Added Filter to class selection dialog
Fixed or removed some minor todo's

PettingZoo.Core/Generator/IExampleGenerator.cs

@@ -1,4 +1,5 @@
 using System;
+using PettingZoo.Core.Validation;
 
 namespace PettingZoo.Core.Generator
 {
@@ -20,14 +21,11 @@ namespace PettingZoo.Core.Generator
         public string? Namespace { get; }
         public string ClassName { get; }
 
-        public string FullClassName => !string.IsNullOrEmpty(Namespace) ? Namespace + "." : "" + ClassName;
+        public string FullClassName => (!string.IsNullOrEmpty(Namespace) ? Namespace + "." : "") + ClassName;
     }
 
 
-    /*
-    public interface IValidatingExample : IExample
+    public interface IValidatingExample : IExample, IPayloadValidator
     {
-        bool Validate(string payload, out string validationMessage);
     }
-    */
 }

PettingZoo.Core/Rendering/MessageBodyRenderer.cs

@@ -18,8 +18,6 @@ namespace PettingZoo.Core.Rendering
             return contentType != null && ContentTypeHandlers.TryGetValue(contentType, out var handler)
                 ? handler(body) 
                 : Encoding.UTF8.GetString(body);
-
-            // ToDo hex output if required
         }
 
 

PettingZoo.Core/Validation/IPayloadValidator.cs

@@ -0,0 +1,25 @@
+using System;
+
+namespace PettingZoo.Core.Validation
+{
+    public class PayloadValidationException : Exception
+    {
+        public TextPosition? ErrorPosition { get; }
+
+
+        public PayloadValidationException(string message, TextPosition? errorPosition) : base(message)
+        {
+            ErrorPosition = errorPosition;
+        }
+    }
+
+
+
+    public interface IPayloadValidator
+    {
+        bool CanValidate();
+
+        /// <exception cref="PayloadValidationException" />
+        void Validate(string payload);
+    }
+}

PettingZoo.Core/Validation/TextPosition.cs

@@ -1,6 +1,6 @@
 using System;
 
-namespace PettingZoo.UI
+namespace PettingZoo.Core.Validation
 {
     public readonly struct TextPosition : IEquatable<TextPosition>
     {

PettingZoo.Tapeti/AssemblyParser/AssemblyParser.cs

@@ -1,44 +1,55 @@
 using System;
 using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
 using System.IO;
 using System.Linq;
 using System.Runtime.Loader;
 using Newtonsoft.Json;
 using PettingZoo.Core.Generator;
+using PettingZoo.Core.Validation;
 
 namespace PettingZoo.Tapeti.AssemblyParser
 {
     public class AssemblyParser : IDisposable
     {
-        private readonly AssemblyLoadContext loadContext;
+        private readonly string[] extraAssembliesPaths;
+        private AssemblyLoadContext? loadContext;
+
 
         public AssemblyParser(params string[] extraAssembliesPaths)
         {
-            // Using the MetadataLoadContext introduces extra complexity since types can not be compared
-            // (a string from the loaded assembly does not equal our typeof(string) for example).
-            // So instead we'll use a regular AssemblyLoadContext. Not ideal, and will probably cause other side-effects
-            // if we're not careful, but I don't feel like writing a full metadata parser right now.
-            // If you have a better idea, it's open-source! :-)
-            loadContext = new AssemblyLoadContext(null, true);
-
-            foreach (var extraAssembly in extraAssembliesPaths.SelectMany(p => Directory.Exists(p)
-                         ? Directory.GetFiles(p, "*.dll")
-                         : Enumerable.Empty<string>()))
-            {
-                loadContext.LoadFromAssemblyPath(extraAssembly);
-            }
+            this.extraAssembliesPaths = extraAssembliesPaths;
         }
 
 
         public void Dispose()
         {
-            loadContext.Unload();
+            loadContext?.Unload();
             GC.SuppressFinalize(this);
         }
 
 
         public IEnumerable<IClassTypeExample> GetExamples(Stream assemblyStream)
         {
+            if (loadContext == null)
+            {
+                /*
+                    Using the MetadataLoadContext introduces extra complexity since types can not be compared
+                    (a string from the loaded assembly does not equal our typeof(string) for example).
+                    So instead we'll use a regular AssemblyLoadContext. Not ideal, and will probably cause other side-effects
+                    if we're not careful, but I don't feel like writing a full metadata parser right now.
+                    If you have a better idea, it's open-source! :-)
+                */
+                loadContext = new AssemblyLoadContext(null, true);
+
+                foreach (var extraAssembly in extraAssembliesPaths.SelectMany(p => Directory.Exists(p)
+                             ? Directory.GetFiles(p, "*.dll")
+                             : Enumerable.Empty<string>()))
+                {
+                    loadContext.LoadFromAssemblyPath(extraAssembly);
+                }
+            }
+
             var assembly = loadContext.LoadFromStream(assemblyStream);
 
             foreach (var type in assembly.GetTypes().Where(t => t.IsClass))
@@ -47,7 +58,7 @@ namespace PettingZoo.Tapeti.AssemblyParser
 
 
 
-        private class TypeExample : IClassTypeExample
+        private class TypeExample : IClassTypeExample, IValidatingExample
         {
             public string AssemblyName => type.Assembly.GetName().Name ?? "";
             public string? Namespace => type.Namespace;
@@ -55,6 +66,9 @@ namespace PettingZoo.Tapeti.AssemblyParser
 
             private readonly Type type;
 
+            private bool validationInitialized;
+            private bool validationAvailable;
+
 
             public TypeExample(Type type)
             {
@@ -64,20 +78,85 @@ namespace PettingZoo.Tapeti.AssemblyParser
 
             public string Generate()
             {
-                /*
-                  We can't create an instance of the type to serialize easily, as most will depend on
-                  assemblies not included in the NuGet package, so we'll parse the Type ourselves.
-                  This is still much easier than using MetadataReader, as we can more easily check against
-                  standard types like Nullable.
-                
-                  The only external dependencies should be the attributes, like [RequiredGuid]. The messaging models
-                  themselves should not inherit from classes outside of their assembly, or include properties
-                  with types from other assemblies. With that assumption, walking the class structure should be safe.
-                  The extraAssemblies passed to TapetiClassLibraryExampleSource can also be used to give it a better chance.
-                */
                 var serialized = TypeToJObjectConverter.Convert(type);
                 return serialized.ToString(Formatting.Indented);
             }
+
+
+            public bool CanValidate()
+            {
+                return InitializeValidation();
+            }
+
+
+            public void Validate(string payload)
+            {
+                if (!InitializeValidation())
+                    return;
+
+                // Json exceptions are already handled by the PayloadEditorViewModel
+                var deserialized = JsonConvert.DeserializeObject(payload, type);
+                if (deserialized == null)
+                    throw new PayloadValidationException(AssemblyParserStrings.JsonDeserializationNull, null);
+
+                try
+                {
+                    var validationContext = new ValidationContext(deserialized);
+                    Validator.ValidateObject(deserialized, validationContext, true);
+                }
+                catch (ValidationException e)
+                {
+                    var members = string.Join(", ", e.ValidationResult.MemberNames);
+                    if (!string.IsNullOrEmpty(members))
+                        throw new PayloadValidationException(string.Format(AssemblyParserStrings.ValidationErrorsMembers, members, e.ValidationResult.ErrorMessage), null);
+
+                    throw new PayloadValidationException(string.Format(AssemblyParserStrings.ValidationErrors, e.ValidationResult.ErrorMessage), null);
+                }
+            }
+
+
+            private bool InitializeValidation()
+            {
+                if (validationInitialized)
+                    return validationAvailable;
+
+                // Attempt to create an instance (only works if all dependencies are present, which is not yet
+                // guaranteed because we aren't fetching NuGet dependencies yet). We're giving it a fighting chance
+                // by referencing Tapeti.Annotations, System.ComponentModel.Annotations and Tapeti.DataAnnotations.Extensions in
+                // this class library.
+                try
+                {
+                    var instance = Activator.CreateInstance(type);
+                    if (instance != null)
+                    {
+                        // Attributes are only evaluated when requested, so call validation once to give it a better chance to
+                        // detect if we'll be able to validate the message
+                        try
+                        {
+                            var validationContext = new ValidationContext(instance);
+                            Validator.ValidateObject(instance, validationContext, true);
+
+                            validationAvailable = true;
+                        }
+                        catch (ValidationException)
+                        {
+                            // The fact that it validated is good enough, this can be expected with an empty object
+                            validationAvailable = true;
+                        }
+                        catch (Exception)
+                        {
+                            // ignored
+                        }
+                    }
+                }
+                catch (Exception)
+                {
+                    // No go, try to create an example without validation
+                }
+
+                validationInitialized = true;
+                return validationAvailable;
+            }
         }
     }
 }

PettingZoo.Tapeti/AssemblyParser/AssemblyParserStrings.Designer.cs

@@ -0,0 +1,90 @@
+//------------------------------------------------------------------------------
+// <auto-generated>
+//     This code was generated by a tool.
+//     Runtime Version:4.0.30319.42000
+//
+//     Changes to this file may cause incorrect behavior and will be lost if
+//     the code is regenerated.
+// </auto-generated>
+//------------------------------------------------------------------------------
+
+namespace PettingZoo.Tapeti.AssemblyParser {
+    using System;
+    
+    
+    /// <summary>
+    ///   A strongly-typed resource class, for looking up localized strings, etc.
+    /// </summary>
+    // This class was auto-generated by the StronglyTypedResourceBuilder
+    // class via a tool like ResGen or Visual Studio.
+    // To add or remove a member, edit your .ResX file then rerun ResGen
+    // with the /str option, or rebuild your VS project.
+    [global::System.CodeDom.Compiler.GeneratedCodeAttribute("System.Resources.Tools.StronglyTypedResourceBuilder", "17.0.0.0")]
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
+    [global::System.Runtime.CompilerServices.CompilerGeneratedAttribute()]
+    internal class AssemblyParserStrings {
+        
+        private static global::System.Resources.ResourceManager resourceMan;
+        
+        private static global::System.Globalization.CultureInfo resourceCulture;
+        
+        [global::System.Diagnostics.CodeAnalysis.SuppressMessageAttribute("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")]
+        internal AssemblyParserStrings() {
+        }
+        
+        /// <summary>
+        ///   Returns the cached ResourceManager instance used by this class.
+        /// </summary>
+        [global::System.ComponentModel.EditorBrowsableAttribute(global::System.ComponentModel.EditorBrowsableState.Advanced)]
+        internal static global::System.Resources.ResourceManager ResourceManager {
+            get {
+                if (object.ReferenceEquals(resourceMan, null)) {
+                    global::System.Resources.ResourceManager temp = new global::System.Resources.ResourceManager("PettingZoo.Tapeti.AssemblyParser.AssemblyParserStrings", typeof(AssemblyParserStrings).Assembly);
+                    resourceMan = temp;
+                }
+                return resourceMan;
+            }
+        }
+        
+        /// <summary>
+        ///   Overrides the current thread's CurrentUICulture property for all
+        ///   resource lookups using this strongly typed resource class.
+        /// </summary>
+        [global::System.ComponentModel.EditorBrowsableAttribute(global::System.ComponentModel.EditorBrowsableState.Advanced)]
+        internal static global::System.Globalization.CultureInfo Culture {
+            get {
+                return resourceCulture;
+            }
+            set {
+                resourceCulture = value;
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to JSON deserialization returned null.
+        /// </summary>
+        internal static string JsonDeserializationNull {
+            get {
+                return ResourceManager.GetString("JsonDeserializationNull", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Failed validation: {0}.
+        /// </summary>
+        internal static string ValidationErrors {
+            get {
+                return ResourceManager.GetString("ValidationErrors", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Failed validation for {0}: {1}.
+        /// </summary>
+        internal static string ValidationErrorsMembers {
+            get {
+                return ResourceManager.GetString("ValidationErrorsMembers", resourceCulture);
+            }
+        }
+    }
+}

PettingZoo.Tapeti/AssemblyParser/AssemblyParserStrings.resx

@@ -0,0 +1,129 @@
+<?xml version="1.0" encoding="utf-8"?>
+<root>
+  <!-- 
+    Microsoft ResX Schema 
+    
+    Version 2.0
+    
+    The primary goals of this format is to allow a simple XML format 
+    that is mostly human readable. The generation and parsing of the 
+    various data types are done through the TypeConverter classes 
+    associated with the data types.
+    
+    Example:
+    
+    ... ado.net/XML headers & schema ...
+    <resheader name="resmimetype">text/microsoft-resx</resheader>
+    <resheader name="version">2.0</resheader>
+    <resheader name="reader">System.Resources.ResXResourceReader, System.Windows.Forms, ...</resheader>
+    <resheader name="writer">System.Resources.ResXResourceWriter, System.Windows.Forms, ...</resheader>
+    <data name="Name1"><value>this is my long string</value><comment>this is a comment</comment></data>
+    <data name="Color1" type="System.Drawing.Color, System.Drawing">Blue</data>
+    <data name="Bitmap1" mimetype="application/x-microsoft.net.object.binary.base64">
+        <value>[base64 mime encoded serialized .NET Framework object]</value>
+    </data>
+    <data name="Icon1" type="System.Drawing.Icon, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
+        <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
+        <comment>This is a comment</comment>
+    </data>
+                
+    There are any number of "resheader" rows that contain simple 
+    name/value pairs.
+    
+    Each data row contains a name, and value. The row also contains a 
+    type or mimetype. Type corresponds to a .NET class that support 
+    text/value conversion through the TypeConverter architecture. 
+    Classes that don't support this are serialized and stored with the 
+    mimetype set.
+    
+    The mimetype is used for serialized objects, and tells the 
+    ResXResourceReader how to depersist the object. This is currently not 
+    extensible. For a given mimetype the value must be set accordingly:
+    
+    Note - application/x-microsoft.net.object.binary.base64 is the format 
+    that the ResXResourceWriter will generate, however the reader can 
+    read any of the formats listed below.
+    
+    mimetype: application/x-microsoft.net.object.binary.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
+            : and then encoded with base64 encoding.
+    
+    mimetype: application/x-microsoft.net.object.soap.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
+            : and then encoded with base64 encoding.
+
+    mimetype: application/x-microsoft.net.object.bytearray.base64
+    value   : The object must be serialized into a byte array 
+            : using a System.ComponentModel.TypeConverter
+            : and then encoded with base64 encoding.
+    -->
+  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
+    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
+    <xsd:element name="root" msdata:IsDataSet="true">
+      <xsd:complexType>
+        <xsd:choice maxOccurs="unbounded">
+          <xsd:element name="metadata">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" />
+              </xsd:sequence>
+              <xsd:attribute name="name" use="required" type="xsd:string" />
+              <xsd:attribute name="type" type="xsd:string" />
+              <xsd:attribute name="mimetype" type="xsd:string" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="assembly">
+            <xsd:complexType>
+              <xsd:attribute name="alias" type="xsd:string" />
+              <xsd:attribute name="name" type="xsd:string" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="data">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
+              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
+              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="resheader">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" />
+            </xsd:complexType>
+          </xsd:element>
+        </xsd:choice>
+      </xsd:complexType>
+    </xsd:element>
+  </xsd:schema>
+  <resheader name="resmimetype">
+    <value>text/microsoft-resx</value>
+  </resheader>
+  <resheader name="version">
+    <value>2.0</value>
+  </resheader>
+  <resheader name="reader">
+    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <resheader name="writer">
+    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <data name="JsonDeserializationNull" xml:space="preserve">
+    <value>JSON deserialization returned null</value>
+  </data>
+  <data name="ValidationErrors" xml:space="preserve">
+    <value>Failed validation: {0}</value>
+  </data>
+  <data name="ValidationErrorsMembers" xml:space="preserve">
+    <value>Failed validation for {0}: {1}</value>
+  </data>
+</root>

PettingZoo.Tapeti/NuGet/NuGetPackageManager.cs

@@ -27,6 +27,7 @@ namespace PettingZoo.Tapeti.NuGet
         public NuGetPackageManager(ILogger logger)
         {
             this.logger = logger;
+
             cache = new SourceCacheContext();
             sources = new List<Source>
             {

PettingZoo.Tapeti/PettingZoo.Tapeti.csproj

@@ -9,6 +9,7 @@
 
   <ItemGroup>
     <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
+    <PackageReference Include="NuGet.PackageManagement" Version="6.0.0" />
     <PackageReference Include="NuGet.Packaging" Version="6.0.0" />
     <PackageReference Include="NuGet.Protocol" Version="6.0.0" />
     <PackageReference Include="Serilog" Version="2.10.0" />
@@ -16,6 +17,7 @@
     <PackageReference Include="System.ComponentModel.Annotations" Version="5.0.0" />
     <PackageReference Include="System.Reactive" Version="5.0.0" />
     <PackageReference Include="System.Reflection.MetadataLoadContext" Version="6.0.0" />
+    <PackageReference Include="Tapeti.Annotations" Version="3.0.0" />
     <PackageReference Include="Tapeti.DataAnnotations.Extensions" Version="3.0.0" />
   </ItemGroup>
 
@@ -25,6 +27,11 @@
   </ItemGroup>
 
   <ItemGroup>
+    <Compile Update="AssemblyParser\AssemblyParserStrings.Designer.cs">
+      <DesignTime>True</DesignTime>
+      <AutoGen>True</AutoGen>
+      <DependentUpon>AssemblyParserStrings.resx</DependentUpon>
+    </Compile>
     <Compile Update="UI\ClassSelection\ClassSelectionStrings.Designer.cs">
       <DesignTime>True</DesignTime>
       <AutoGen>True</AutoGen>
@@ -46,6 +53,10 @@
   </ItemGroup>
 
   <ItemGroup>
+    <EmbeddedResource Update="AssemblyParser\AssemblyParserStrings.resx">
+      <Generator>ResXFileCodeGenerator</Generator>
+      <LastGenOutput>AssemblyParserStrings.Designer.cs</LastGenOutput>
+    </EmbeddedResource>
     <EmbeddedResource Update="UI\ClassSelection\ClassSelectionStrings.resx">
       <Generator>PublicResXFileCodeGenerator</Generator>
       <LastGenOutput>ClassSelectionStrings.Designer.cs</LastGenOutput>

PettingZoo.Tapeti/TapetiClassLibraryExampleGenerator.cs

@@ -51,7 +51,7 @@ namespace PettingZoo.Tapeti
 
                     var progressWindow = new PackageProgressWindow();
                     progressWindow.Left = windowBounds.Left + (windowBounds.Width - progressWindow.Width) / 2;
-                    progressWindow.Left = windowBounds.Top + (windowBounds.Height - progressWindow.Height) / 2;
+                    progressWindow.Top = windowBounds.Top + (windowBounds.Height - progressWindow.Height) / 2;
                     progressWindow.Show();
 
                     Task.Run(async () =>

PettingZoo.Tapeti/TypeToJObjectConverter.cs

@@ -43,9 +43,6 @@ namespace PettingZoo.Tapeti
 
             foreach (var propertyInfo in classType.GetProperties(BindingFlags.Public | BindingFlags.Instance))
             {
-                // Note: unfortunately we can not call GetCustomAttributes here for now, as that would
-                // trigger assemblies not included in the package to be loaded, which may not exist
-
                 var value = TypeToJToken(propertyInfo.PropertyType, newTypesEncountered);
                 result.Add(propertyInfo.Name, value);
             }
@@ -62,6 +59,8 @@ namespace PettingZoo.Tapeti
                 actualType = equivalentType;
 
 
+            // TODO check for JsonConverter attribute? doubt we'll be able to generate a nice value for it, but at least we can provide a placeholder
+
             // String is also a class
             if (actualType == typeof(string))
                 return "";

PettingZoo.Tapeti/UI/ClassSelection/ClassSelectionStrings.Designer.cs

@@ -78,6 +78,24 @@ namespace PettingZoo.Tapeti.UI.ClassSelection {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Only classes ending in &quot;Message&quot;.
+        /// </summary>
+        public static string CheckboxMessageOnly {
+            get {
+                return ResourceManager.GetString("CheckboxMessageOnly", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Filter.
+        /// </summary>
+        public static string LabelFilter {
+            get {
+                return ResourceManager.GetString("LabelFilter", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Select class.
         /// </summary>

PettingZoo.Tapeti/UI/ClassSelection/ClassSelectionStrings.resx

@@ -112,10 +112,10 @@
     <value>2.0</value>
   </resheader>
   <resheader name="reader">
-    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
   </resheader>
   <resheader name="writer">
-    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
   </resheader>
   <data name="ButtonCancel" xml:space="preserve">
     <value>Cancel</value>
@@ -123,6 +123,12 @@
   <data name="ButtonSelect" xml:space="preserve">
     <value>Select</value>
   </data>
+  <data name="CheckboxMessageOnly" xml:space="preserve">
+    <value>Only classes ending in "Message"</value>
+  </data>
+  <data name="LabelFilter" xml:space="preserve">
+    <value>Filter</value>
+  </data>
   <data name="WindowTitle" xml:space="preserve">
     <value>Select class</value>
   </data>

PettingZoo.Tapeti/UI/ClassSelection/ClassSelectionViewModel.cs

@@ -1,7 +1,11 @@
 using System;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
+using System.ComponentModel;
+using System.Diagnostics.CodeAnalysis;
 using System.Linq;
+using System.Reactive.Linq;
+using System.Threading;
 using System.Windows.Input;
 using PettingZoo.Core.Generator;
 using PettingZoo.WPF.ViewModel;
@@ -13,8 +17,34 @@ namespace PettingZoo.Tapeti.UI.ClassSelection
         private BaseClassTreeItem? selectedItem;
         private readonly DelegateCommand selectCommand;
 
+        private string filterText = "";
+        private bool filterMessageOnly = true;
+        private ObservableCollection<BaseClassTreeItem> filteredExamples;
+
         public ObservableCollection<BaseClassTreeItem> Examples { get; } = new();
 
+        public string FilterText
+        {
+            get => filterText;
+            set => SetField(ref filterText, value);
+        }
+
+
+        public bool FilterMessageOnly
+        {
+            get => filterMessageOnly;
+            set => SetField(ref filterMessageOnly, value);
+        }
+
+        public ObservableCollection<BaseClassTreeItem> FilteredExamples
+        {
+            get => filteredExamples;
+
+            [MemberNotNull(nameof(filteredExamples))]
+            set => SetField(ref filteredExamples!, value);
+        }
+
+
         public BaseClassTreeItem? SelectedItem
         {
             get => selectedItem; 
@@ -39,6 +69,29 @@ namespace PettingZoo.Tapeti.UI.ClassSelection
             selectCommand = new DelegateCommand(SelectExecute, SelectCanExecute);
 
             TreeFromExamples(examples);
+
+            Observable.FromEventPattern<PropertyChangedEventHandler, PropertyChangedEventArgs>(
+                h => PropertyChanged += h,
+                h => PropertyChanged -= h)
+                .Where(e => e.EventArgs.PropertyName is nameof(FilterText) or nameof(FilterMessageOnly))
+                .Throttle(TimeSpan.FromMilliseconds(250))
+                .ObserveOn(SynchronizationContext.Current!)
+                .Subscribe(_ => UpdateFilteredExamples());
+
+            UpdateFilteredExamples();
+        }
+
+
+        [MemberNotNull(nameof(filteredExamples))]
+        private void UpdateFilteredExamples()
+        {
+            if (!FilterMessageOnly && string.IsNullOrWhiteSpace(FilterText))
+                FilteredExamples = Examples;
+
+            FilteredExamples = new ObservableCollection<BaseClassTreeItem>(Examples
+                .Select(i => i.Filter(FilterText, FilterMessageOnly))
+                .Where(i => i != null)
+                .Cast<BaseClassTreeItem>());
         }
 
 
@@ -109,7 +162,7 @@ namespace PettingZoo.Tapeti.UI.ClassSelection
     }
 
 
-    public class BaseClassTreeItem
+    public abstract class BaseClassTreeItem
     {
         private readonly SortedSet<BaseClassTreeItem> children = new(new BaseClassTreeItemComparer());
 
@@ -117,7 +170,7 @@ namespace PettingZoo.Tapeti.UI.ClassSelection
         public IReadOnlyCollection<BaseClassTreeItem> Children => children;
 
 
-        public BaseClassTreeItem(string name)
+        protected BaseClassTreeItem(string name)
         {
             Name = name;
         }
@@ -127,6 +180,9 @@ namespace PettingZoo.Tapeti.UI.ClassSelection
         {
             children.Add(item);
         }
+
+
+        public abstract BaseClassTreeItem? Filter(string filterText, bool messageOnly);
     }
 
 
@@ -142,6 +198,32 @@ namespace PettingZoo.Tapeti.UI.ClassSelection
             Name = string.IsNullOrEmpty(parentFolderName) ? Name : parentFolderName + "." + Name;
             return this;
         }
+
+
+        public override BaseClassTreeItem? Filter(string filterText, bool messageOnly)
+        {
+            var childFilterText = filterText;
+
+            // If the folder name matches, include everything in it (...that matches messageOnly)
+            if (!string.IsNullOrWhiteSpace(filterText) && Name.Contains(filterText, StringComparison.CurrentCultureIgnoreCase))
+                childFilterText = "";
+
+            var filteredChildren = Children
+                .Select(c => c.Filter(childFilterText, messageOnly))
+                .Where(c => c != null)
+                .Cast<BaseClassTreeItem>();
+
+            var result = new NamespaceFolderClassTreeItem(Name);
+            var hasChildren = false;
+
+            foreach (var filteredChild in filteredChildren)
+            {
+                result.AddChild(filteredChild);
+                hasChildren = true;
+            }
+
+            return hasChildren ? result : null;
+        }
     }
 
 
@@ -154,6 +236,18 @@ namespace PettingZoo.Tapeti.UI.ClassSelection
         {
             Example = example;
         }
+
+
+        public override BaseClassTreeItem? Filter(string filterText, bool messageOnly)
+        {
+            // Assumes examples don't have child items, so no further filtering is required
+            if (messageOnly && !Name.EndsWith(@"Message", StringComparison.CurrentCultureIgnoreCase))
+                return null;
+
+            return string.IsNullOrWhiteSpace(filterText) || Name.Contains(filterText, StringComparison.CurrentCultureIgnoreCase) 
+                ? this 
+                : null;
+        }
     }
 
 

PettingZoo.Tapeti/UI/ClassSelection/ClassSelectionWindow.xaml

@@ -12,7 +12,8 @@
         Width="800"
         ResizeMode="CanResizeWithGrip"
         WindowStartupLocation="CenterOwner"
-        d:DataContext="{d:DesignInstance classSelection:DesignTimeClassSelectionViewModel, IsDesignTimeCreatable=True}">
+        d:DataContext="{d:DesignInstance classSelection:DesignTimeClassSelectionViewModel, IsDesignTimeCreatable=True}"
+        FocusManager.FocusedElement="{Binding ElementName=DefaultFocus}">
     <Window.Resources>
         <ResourceDictionary>
             <Style x:Key="TreeItemIcon" TargetType="{x:Type Image}">
@@ -31,11 +32,24 @@
 
     <controls:GridLayout Style="{StaticResource Form}" Margin="8">
         <Grid.RowDefinitions>
+            <RowDefinition Height="Auto" />
+            <RowDefinition Height="Auto"/>
+            <RowDefinition Height="8"/>
             <RowDefinition Height="*" />
             <RowDefinition Height="Auto" />
         </Grid.RowDefinitions>
 
-        <TreeView Grid.Row="0" ItemsSource="{Binding Examples}" SelectedItemChanged="TreeView_OnSelectedItemChanged">
+        <Grid.ColumnDefinitions>
+            <ColumnDefinition Width="Auto" />
+            <ColumnDefinition Width="*" />
+        </Grid.ColumnDefinitions>
+
+        <Label Grid.Row="0" Grid.Column="0" Content="{x:Static classSelection:ClassSelectionStrings.LabelFilter}" />
+        <TextBox Grid.Row="0" Grid.Column="1" Text="{Binding FilterText, UpdateSourceTrigger=PropertyChanged}" x:Name="DefaultFocus" />
+
+        <CheckBox Grid.Row="1" Grid.Column="1" Content="{x:Static classSelection:ClassSelectionStrings.CheckboxMessageOnly}" IsChecked="{Binding FilterMessageOnly}" />
+
+        <TreeView Grid.Row="3" Grid.Column="0" Grid.ColumnSpan="2" ItemsSource="{Binding FilteredExamples}" SelectedItemChanged="TreeView_OnSelectedItemChanged">
             <TreeView.ItemContainerStyle>
                 <Style TargetType="{x:Type TreeViewItem}">
                     <Setter Property="IsExpanded" Value="True" />
@@ -54,6 +68,11 @@
                 </HierarchicalDataTemplate>
                 <HierarchicalDataTemplate DataType="{x:Type classSelection:ExampleTreeItem}">
                     <StackPanel Orientation="Horizontal">
+                        <StackPanel.InputBindings>
+                            <MouseBinding 
+                                MouseAction="LeftDoubleClick" 
+                                Command="{Binding DataContext.SelectCommand, RelativeSource={RelativeSource AncestorType={x:Type TreeView}}}" />
+                        </StackPanel.InputBindings>
                         <Image Source="{svgc:SvgImage Source=/Images/Example.svg, AppName=PettingZoo}" Width="16" Height="16" Style="{StaticResource TreeItemIcon}"/>
                         <TextBlock Text="{Binding Name}" Style="{StaticResource TreeItemLabel}" />
                     </StackPanel>
@@ -61,9 +80,9 @@
             </TreeView.Resources>
         </TreeView>
 
-        <StackPanel Grid.Row="1" Orientation="Horizontal" HorizontalAlignment="Right" Style="{StaticResource FooterPanel}">
+        <StackPanel Grid.Row="4" Grid.Column="0" Grid.ColumnSpan="2" Orientation="Horizontal" HorizontalAlignment="Right" Style="{StaticResource FooterPanel}">
             <Button Content="{x:Static classSelection:ClassSelectionStrings.ButtonSelect}" Style="{StaticResource FooterButton}" Command="{Binding SelectCommand}" />
-            <Button Content="{x:Static classSelection:ClassSelectionStrings.ButtonCancel}"  Style="{StaticResource FooterButton}" />
+            <Button IsCancel="True" Content="{x:Static classSelection:ClassSelectionStrings.ButtonCancel}" Style="{StaticResource FooterButton}" />
         </StackPanel>
     </controls:GridLayout>
 </Window>

PettingZoo.Tapeti/UI/PackageSelection/PackageSelectionWindow.xaml

@@ -8,10 +8,11 @@
         mc:Ignorable="d" 
         Title="{x:Static packageSelection:PackageSelectionStrings.WindowTitle}" 
         Height="600" 
-        Width="800"
+        Width="600"
         ResizeMode="CanResizeWithGrip"
         WindowStartupLocation="CenterOwner"
-        d:DataContext="{d:DesignInstance packageSelection:DesignTimePackageSelectionViewModel, IsDesignTimeCreatable=True}">
+        d:DataContext="{d:DesignInstance packageSelection:DesignTimePackageSelectionViewModel, IsDesignTimeCreatable=True}"
+        FocusManager.FocusedElement="{Binding ElementName=DefaultFocus}">
     <Window.Resources>
         <ResourceDictionary>
             <Style x:Key="PackageTitle" TargetType="{x:Type TextBlock}">
@@ -28,6 +29,10 @@
                 <Setter Property="TextTrimming" Value="CharacterEllipsis" />
             </Style>
 
+            <Style x:Key="Hint" TargetType="{x:Type TextBlock}">
+                <Setter Property="Foreground" Value="{x:Static SystemColors.GrayTextBrush}" />
+            </Style>
+
             <ResourceDictionary.MergedDictionaries>
                 <ResourceDictionary Source="pack://application:,,,/PettingZoo.WPF;component/Style.xaml"/>
             </ResourceDictionary.MergedDictionaries>
@@ -68,7 +73,7 @@
             </ComboBox.ItemTemplate>
         </ComboBox>
 
-        <TextBox Grid.Row="5" Grid.Column="1" Grid.ColumnSpan="2" Text="{Binding NuGetSearchTerm, UpdateSourceTrigger=PropertyChanged}" />
+        <TextBox Grid.Row="5" Grid.Column="1" Grid.ColumnSpan="2" Text="{Binding NuGetSearchTerm, UpdateSourceTrigger=PropertyChanged}" x:Name="DefaultFocus" />
         <TextBlock Grid.Row="5" Grid.Column="1" Grid.ColumnSpan="2" Text="{x:Static packageSelection:PackageSelectionStrings.PlaceholderNuGetSearch}" Visibility="{Binding NuGetSearchTermPlaceholderVisibility}" Style="{StaticResource Placeholder}" />
 
         <CheckBox Grid.Row="6" Grid.Column="1" Grid.ColumnSpan="2" Content="{x:Static packageSelection:PackageSelectionStrings.CheckPrerelease}" IsChecked="{Binding NuGetIncludePrerelease}" />
@@ -82,6 +87,11 @@
             <ListBox.ItemTemplate>
                 <DataTemplate>
                     <Grid>
+                        <Grid.InputBindings>
+                            <MouseBinding 
+                                MouseAction="LeftDoubleClick" 
+                                Command="{Binding DataContext.SelectCommand, RelativeSource={RelativeSource AncestorType={x:Type ListBox}}}" />
+                        </Grid.InputBindings>
                         <Grid.RowDefinitions>
                             <RowDefinition Height="Auto" />
                             <RowDefinition Height="Auto" />
@@ -116,11 +126,11 @@
             </ComboBox.ItemTemplate>
         </ComboBox>
 
-        <TextBlock Grid.Row="10" Grid.Column="1" Grid.ColumnSpan="2" Text="{Binding HintNuGetSources}" TextWrapping="Wrap" />
+        <TextBlock Grid.Row="10" Grid.Column="1" Grid.ColumnSpan="2" Text="{Binding HintNuGetSources}" TextWrapping="Wrap" Style="{StaticResource Hint}" />
 
         <StackPanel Grid.Row="11" Grid.Column="0" Grid.ColumnSpan="3" Orientation="Horizontal" HorizontalAlignment="Right" Style="{StaticResource FooterPanel}">
             <Button Content="{x:Static packageSelection:PackageSelectionStrings.ButtonSelect}" Style="{StaticResource FooterButton}" Command="{Binding SelectCommand}" />
-            <Button Content="{x:Static packageSelection:PackageSelectionStrings.ButtonCancel}"  Style="{StaticResource FooterButton}" />
+            <Button IsCancel="True" Content="{x:Static packageSelection:PackageSelectionStrings.ButtonCancel}"  Style="{StaticResource FooterButton}" />
         </StackPanel>
     </controls:GridLayout>
 </Window>

PettingZoo/TODO.md

@@ -11,5 +11,4 @@ Should-have
 
 
 Nice-to-have
-------------
-- Validation against message classes (for Tapeti messages)
+------------

PettingZoo/UI/ErrorHighlightingTransformer.cs

@@ -2,6 +2,7 @@
 using System.Windows.Media;
 using ICSharpCode.AvalonEdit.Document;
 using ICSharpCode.AvalonEdit.Rendering;
+using PettingZoo.Core.Validation;
 
 namespace PettingZoo.UI
 {

PettingZoo/UI/Subscribe/SubscribeViewModel.cs

@@ -2,8 +2,6 @@
 using System.Windows.Input;
 using PettingZoo.WPF.ViewModel;
 
-// TODO validate input
-
 namespace PettingZoo.UI.Subscribe
 {
     public class SubscribeViewModel : BaseViewModel
@@ -11,28 +9,30 @@ namespace PettingZoo.UI.Subscribe
         private string exchange;
         private string routingKey;
 
+        private readonly DelegateCommand okCommand;
+
 
         public string Exchange
         {
             get => exchange;
-            set => SetField(ref exchange, value);
+            set => SetField(ref exchange, value, delegateCommandsChanged: new [] { okCommand });
         }
 
         public string RoutingKey
         {
             get => routingKey;
-            set => SetField(ref routingKey, value);
+            set => SetField(ref routingKey, value, delegateCommandsChanged: new[] { okCommand });
         }
 
 
-        public ICommand OkCommand { get; }
+        public ICommand OkCommand => okCommand;
 
         public event EventHandler? OkClick;
 
 
         public SubscribeViewModel(SubscribeDialogParams subscribeParams)
         {
-            OkCommand = new DelegateCommand(OkExecute, OkCanExecute);
+            okCommand = new DelegateCommand(OkExecute, OkCanExecute);
             
             exchange = subscribeParams.Exchange;
             routingKey = subscribeParams.RoutingKey;
@@ -51,9 +51,9 @@ namespace PettingZoo.UI.Subscribe
         }
 
 
-        private static bool OkCanExecute()
+        private bool OkCanExecute()
         {
-            return true;
+            return !string.IsNullOrWhiteSpace(Exchange) && !string.IsNullOrWhiteSpace(RoutingKey);
         }
     }
 

PettingZoo/UI/Subscribe/SubscribeWindow.xaml

@@ -30,10 +30,10 @@
                 <RowDefinition Height="Auto"/>
             </Grid.RowDefinitions>
             <Label Grid.Column="0" Grid.Row="0" Content="{x:Static subscribe:SubscribeWindowStrings.LabelExchange}"/>
-            <TextBox Grid.Column="1" Grid.Row="0" Text="{Binding Exchange}" Name="ExchangeTextBox"/>
+            <TextBox Grid.Column="1" Grid.Row="0" Text="{Binding Exchange, UpdateSourceTrigger=PropertyChanged}" Name="ExchangeTextBox"/>
 
             <Label Grid.Column="0" Grid.Row="1" Content="{x:Static subscribe:SubscribeWindowStrings.LabelRoutingKey}"/>
-            <TextBox Grid.Column="1" Grid.Row="1" Text="{Binding RoutingKey}"/>
+            <TextBox Grid.Column="1" Grid.Row="1" Text="{Binding RoutingKey, UpdateSourceTrigger=PropertyChanged}"/>
         </controls:GridLayout>
     </DockPanel>
 </Window>

PettingZoo/UI/Subscribe/SubscribeWindowStrings.Designer.cs

@@ -19,7 +19,7 @@ namespace PettingZoo.UI.Subscribe {
     // class via a tool like ResGen or Visual Studio.
     // To add or remove a member, edit your .ResX file then rerun ResGen
     // with the /str option, or rebuild your VS project.
-    [global::System.CodeDom.Compiler.GeneratedCodeAttribute("System.Resources.Tools.StronglyTypedResourceBuilder", "16.0.0.0")]
+    [global::System.CodeDom.Compiler.GeneratedCodeAttribute("System.Resources.Tools.StronglyTypedResourceBuilder", "17.0.0.0")]
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
     [global::System.Runtime.CompilerServices.CompilerGeneratedAttribute()]
     public class SubscribeWindowStrings {

PettingZoo/UI/Subscribe/SubscribeWindowStrings.resx

@@ -112,10 +112,10 @@
     <value>2.0</value>
   </resheader>
   <resheader name="reader">
-    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
   </resheader>
   <resheader name="writer">
-    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
   </resheader>
   <data name="ButtonCancel" xml:space="preserve">
     <value>Cancel</value>

PettingZoo/UI/Tab/Publisher/PayloadEditorControl.xaml.cs

@@ -3,6 +3,7 @@ using System.Reactive.Linq;
 using System.Threading;
 using System.Windows;
 using System.Windows.Data;
+using PettingZoo.Core.Validation;
 
 namespace PettingZoo.UI.Tab.Publisher
 {
@@ -87,6 +88,13 @@ namespace PettingZoo.UI.Tab.Publisher
         }
 
 
+        public IPayloadValidator? Validator
+        {
+            get => viewModel.Validator;
+            set => viewModel.Validator = value;
+        }
+
+
         private readonly ErrorHighlightingTransformer errorHighlightingTransformer = new();
 
         public PayloadEditorControl()
@@ -181,7 +189,7 @@ namespace PettingZoo.UI.Tab.Publisher
 
                             errorHighlightingTransformer.ErrorPosition = viewModel.ValidationInfo.ErrorPosition;
 
-                            // TODO this can probably be optimized to only redraw the affected line
+                            // This can probably be optimized to only redraw the affected line, but the message is typically so small it's not worth the effort at the moment
                             Editor.TextArea.TextView.Redraw();
                             break;
 

PettingZoo/UI/Tab/Publisher/PayloadEditorStrings.Designer.cs

@@ -105,6 +105,15 @@ namespace PettingZoo.UI.Tab.Publisher {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Valid syntax.
+        /// </summary>
+        internal static string ValidationOkSyntax {
+            get {
+                return ResourceManager.GetString("ValidationOkSyntax", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Validating....
         /// </summary>

PettingZoo/UI/Tab/Publisher/PayloadEditorStrings.resx

@@ -132,6 +132,9 @@
   <data name="ValidationOk" xml:space="preserve">
     <value>Valid</value>
   </data>
+  <data name="ValidationOkSyntax" xml:space="preserve">
+    <value>Valid syntax</value>
+  </data>
   <data name="ValidationValidating" xml:space="preserve">
     <value>Validating...</value>
   </data>

PettingZoo/UI/Tab/Publisher/PayloadEditorViewModel.cs

@@ -5,6 +5,7 @@ using System.Windows;
 using ICSharpCode.AvalonEdit.Highlighting;
 using Newtonsoft.Json;
 using Newtonsoft.Json.Linq;
+using PettingZoo.Core.Validation;
 using PettingZoo.WPF.ViewModel;
 
 namespace PettingZoo.UI.Tab.Publisher
@@ -22,6 +23,7 @@ namespace PettingZoo.UI.Tab.Publisher
         NotSupported,
         Validating,
         Ok,
+        OkSyntax,
         Error
     }
 
@@ -41,6 +43,7 @@ namespace PettingZoo.UI.Tab.Publisher
                 ValidationStatus.NotSupported => "",
                 ValidationStatus.Validating => PayloadEditorStrings.ValidationValidating,
                 ValidationStatus.Ok => PayloadEditorStrings.ValidationOk,
+                ValidationStatus.OkSyntax => PayloadEditorStrings.ValidationOkSyntax,
                 ValidationStatus.Error => throw new InvalidOperationException(@"Message required for Error validation status"),
                 _ => throw new ArgumentException(@"Unsupported validation status", nameof(status))
             };
@@ -58,7 +61,7 @@ namespace PettingZoo.UI.Tab.Publisher
         private PayloadEditorContentType contentTypeSelection = PayloadEditorContentType.Json;
         private bool fixedJson;
 
-        private ValidationInfo validationInfo = new(ValidationStatus.Ok);
+        private ValidationInfo validationInfo = new(ValidationStatus.OkSyntax);
 
         private string payload = "";
 
@@ -125,7 +128,7 @@ namespace PettingZoo.UI.Tab.Publisher
 
         public string ValidationMessage => ValidationInfo.Message;
         
-        public Visibility ValidationOk => ValidationInfo.Status == ValidationStatus.Ok ? Visibility.Visible : Visibility.Collapsed;
+        public Visibility ValidationOk => ValidationInfo.Status is ValidationStatus.Ok or ValidationStatus.OkSyntax ? Visibility.Visible : Visibility.Collapsed;
         public Visibility ValidationError => ValidationInfo.Status == ValidationStatus.Error ? Visibility.Visible : Visibility.Collapsed;
         public Visibility ValidationValidating => ValidationInfo.Status == ValidationStatus.Validating ? Visibility.Visible : Visibility.Collapsed;
 
@@ -145,6 +148,8 @@ namespace PettingZoo.UI.Tab.Publisher
             : null;
 
 
+        public IPayloadValidator? Validator { get; set; }
+
 
         public PayloadEditorViewModel()
         {
@@ -188,9 +193,28 @@ namespace PettingZoo.UI.Tab.Publisher
             try
             {
                 if (!string.IsNullOrEmpty(Payload))
-                    JToken.Parse(Payload);
-
-                ValidationInfo = new ValidationInfo(ValidationStatus.Ok);
+                {
+                    if (Validator != null && Validator.CanValidate())
+                    {
+                        Validator.Validate(payload);
+                        ValidationInfo = new ValidationInfo(ValidationStatus.Ok);
+                    }
+                    else
+                    {
+                        JToken.Parse(Payload);
+                        ValidationInfo = new ValidationInfo(ValidationStatus.OkSyntax);
+                    }
+                }
+                else
+                    ValidationInfo = new ValidationInfo(ValidationStatus.OkSyntax);
+            }
+            catch (PayloadValidationException e)
+            {
+                ValidationInfo = new ValidationInfo(ValidationStatus.Error, e.Message, e.ErrorPosition);
+            }
+            catch (JsonSerializationException e)
+            {
+                ValidationInfo = new ValidationInfo(ValidationStatus.Error, e.Message, new TextPosition(e.LineNumber, e.LinePosition));
             }
             catch (JsonReaderException e)
             {

PettingZoo/UI/Tab/Publisher/RawPublisherViewModel.cs

@@ -216,12 +216,34 @@ namespace PettingZoo.UI.Tab.Publisher
             {
                 return string.IsNullOrEmpty(value) ? null : value;
             }
-            
-            // TODO check parsing of priority and timestamp
-            
-            var headers = Headers.Where(h => h.IsValid()).ToDictionary(h => h.Key, h => h.Value);
 
-            // TODO background worker / async
+            byte? priorityValue = null;
+            DateTime? timestampValue = null;
+
+            if (!string.IsNullOrWhiteSpace(Priority))
+            {
+                if (byte.TryParse(Priority, out var priorityParsedValue))
+                    priorityValue = priorityParsedValue;
+                else
+                {
+                    MessageBox.Show(RawPublisherViewStrings.PriorityParseFailed, RawPublisherViewStrings.PublishValidationErrorTitle, MessageBoxButton.OK, MessageBoxImage.Error);
+                    return;
+                }
+            }
+
+            if (!string.IsNullOrWhiteSpace(Timestamp))
+            {
+                if (DateTime.TryParse(Timestamp, out var timestampParsedValue))
+                    timestampValue = timestampParsedValue;
+                else
+                {
+                    MessageBox.Show(RawPublisherViewStrings.TimestampParseFailed, RawPublisherViewStrings.PublishValidationErrorTitle, MessageBoxButton.OK, MessageBoxImage.Error);
+                    return;
+                }
+            }
+
+
+            var headers = Headers.Where(h => h.IsValid()).ToDictionary(h => h.Key, h => h.Value);
 
             connection.Publish(new PublishMessageInfo(
                 publishDestination.Exchange, 
@@ -236,9 +258,9 @@ namespace PettingZoo.UI.Tab.Publisher
                     DeliveryMode = deliveryMode,
                     Expiration = NullIfEmpty(Expiration),
                     MessageId = NullIfEmpty(MessageId),
-                    Priority = !string.IsNullOrEmpty(Priority) && byte.TryParse(Priority, out var priorityValue) ? priorityValue : null,
+                    Priority = priorityValue,
                     ReplyTo = publishDestination.GetReplyTo(),
-                    Timestamp = !string.IsNullOrEmpty(Timestamp) && DateTime.TryParse(Timestamp, out var timestampValue) ? timestampValue : null,
+                    Timestamp = timestampValue,
                     Type = NullIfEmpty(TypeProperty),
                     UserId = NullIfEmpty(UserId)
                 }));

PettingZoo/UI/Tab/Publisher/RawPublisherViewStrings.Designer.cs

@@ -222,6 +222,15 @@ namespace PettingZoo.UI.Tab.Publisher {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Priority must be a valid byte value.
+        /// </summary>
+        public static string PriorityParseFailed {
+            get {
+                return ResourceManager.GetString("PriorityParseFailed", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to ⏶ Collapse.
         /// </summary>
@@ -239,5 +248,23 @@ namespace PettingZoo.UI.Tab.Publisher {
                 return ResourceManager.GetString("PropertiesExpand", resourceCulture);
             }
         }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Invalid parameters.
+        /// </summary>
+        public static string PublishValidationErrorTitle {
+            get {
+                return ResourceManager.GetString("PublishValidationErrorTitle", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Timestamp must be a valid date/time value.
+        /// </summary>
+        public static string TimestampParseFailed {
+            get {
+                return ResourceManager.GetString("TimestampParseFailed", resourceCulture);
+            }
+        }
     }
 }

PettingZoo/UI/Tab/Publisher/RawPublisherViewStrings.resx

@@ -112,10 +112,10 @@
     <value>2.0</value>
   </resheader>
   <resheader name="reader">
-    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
   </resheader>
   <resheader name="writer">
-    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
   </resheader>
   <data name="DeliveryModeNonPersistent" xml:space="preserve">
     <value>Transient (non-persistent)</value>
@@ -171,10 +171,19 @@
   <data name="LabelUserId" xml:space="preserve">
     <value>User ID</value>
   </data>
+  <data name="PriorityParseFailed" xml:space="preserve">
+    <value>Priority must be a valid byte value</value>
+  </data>
   <data name="PropertiesCollapse" xml:space="preserve">
     <value>⏶ Collapse</value>
   </data>
   <data name="PropertiesExpand" xml:space="preserve">
     <value>⏷ Expand</value>
   </data>
+  <data name="PublishValidationErrorTitle" xml:space="preserve">
+    <value>Invalid parameters</value>
+  </data>
+  <data name="TimestampParseFailed" xml:space="preserve">
+    <value>Timestamp must be a valid date/time value</value>
+  </data>
 </root>

PettingZoo/UI/Tab/Publisher/TapetiPublisherView.xaml

@@ -46,6 +46,6 @@
         </Grid>
 
         <Label Grid.Row="6" Grid.Column="0" Content="{x:Static publisher:TapetiPublisherViewStrings.LabelPayload}" />
-        <publisher:PayloadEditorControl Grid.Row="6" Grid.Column="1" Payload="{Binding Payload}" FixedJson="True" Height="350"/>
+        <publisher:PayloadEditorControl Grid.Row="6" Grid.Column="1" Payload="{Binding Payload}" FixedJson="True" Height="350" x:Name="PayloadEditor"/>
     </controls:GridLayout>
 </UserControl>

PettingZoo/UI/Tab/Publisher/TapetiPublisherView.xaml.cs

@@ -8,10 +8,13 @@ namespace PettingZoo.UI.Tab.Publisher
     /// </summary>
     public partial class TapetiPublisherView
     {
+        // ReSharper disable once SuggestBaseTypeForParameterInConstructor - the XAML explicitly requires TapetiPublisherViewModel
         public TapetiPublisherView(TapetiPublisherViewModel viewModel)
         {
             DataContext = viewModel;
             InitializeComponent();
+
+            PayloadEditor.Validator = viewModel;
         }
 
 

PettingZoo/UI/Tab/Publisher/TapetiPublisherViewModel.cs

@@ -5,12 +5,13 @@ using System.Windows.Input;
 using System.Windows.Threading;
 using PettingZoo.Core.Connection;
 using PettingZoo.Core.Generator;
+using PettingZoo.Core.Validation;
 using PettingZoo.WPF.ViewModel;
 using IConnection = PettingZoo.Core.Connection.IConnection;
 
 namespace PettingZoo.UI.Tab.Publisher
 {
-    public class TapetiPublisherViewModel : BaseViewModel, ITabHostWindowNotify
+    public class TapetiPublisherViewModel : BaseViewModel, ITabHostWindowNotify, IPayloadValidator
     {
         private readonly IConnection connection;
         private readonly IPublishDestination publishDestination;
@@ -23,6 +24,7 @@ namespace PettingZoo.UI.Tab.Publisher
         private string className = "";
         private string assemblyName = "";
         private Window? tabHostWindow;
+        private IValidatingExample? validatingExample;
 
 
         public string CorrelationId
@@ -35,7 +37,11 @@ namespace PettingZoo.UI.Tab.Publisher
         public string ClassName
         {
             get => string.IsNullOrEmpty(className) ? AssemblyName + "." : className;
-            set => SetField(ref className, value);
+            set
+            {
+                if (SetField(ref className, value))
+                    validatingExample = null;
+            }
         }
 
 
@@ -123,6 +129,8 @@ namespace PettingZoo.UI.Tab.Publisher
                         case IClassTypeExample classTypeExample:
                             AssemblyName = classTypeExample.AssemblyName;
                             ClassName = classTypeExample.FullClassName;
+
+                            validatingExample = classTypeExample as IValidatingExample;
                             break;
                     }
 
@@ -139,8 +147,6 @@ namespace PettingZoo.UI.Tab.Publisher
                 return string.IsNullOrEmpty(value) ? null : value;
             }
             
-            // TODO background worker / async
-
             connection.Publish(new PublishMessageInfo(
                 publishDestination.Exchange,
                 publishDestination.RoutingKey,
@@ -168,6 +174,18 @@ namespace PettingZoo.UI.Tab.Publisher
         {
             tabHostWindow = hostWindow;
         }
+
+
+        public bool CanValidate()
+        {
+            return validatingExample != null && validatingExample.CanValidate();
+        }
+
+
+        public void Validate(string validatePayload)
+        {
+            validatingExample?.Validate(validatePayload);
+        }
     }