Changed payload editor to Avalon

- Syntax highlighting
- Highlight for JSON validation errors
- Much improved tab handling and all the other advantages of using a proper editor

PettingZoo/PettingZoo.csproj

@@ -19,7 +19,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <None Remove="Images\Connecting.svg" />
+    <None Remove="Images\Busy.svg" />
     <None Remove="Images\Dock.svg" />
     <None Remove="Images\Error.svg" />
     <None Remove="Images\Ok.svg" />
@@ -40,6 +40,7 @@
   </ItemGroup>
 
   <ItemGroup>
+    <PackageReference Include="AvalonEdit" Version="6.1.2.30" />
     <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
     <PackageReference Include="SharpVectors" Version="1.7.7" />
     <PackageReference Include="SimpleInjector" Version="5.3.2" />
@@ -54,7 +55,7 @@
 
   <ItemGroup>
     <Resource Include="Images\Undock.svg" />
-    <Resource Include="Images\Connecting.svg" />
+    <Resource Include="Images\Busy.svg" />
   </ItemGroup>
 
   <ItemGroup>

PettingZoo/Style.xaml

@@ -1,6 +1,7 @@
 <ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-                    xmlns:ui="clr-namespace:PettingZoo.UI">
+                    xmlns:ui="clr-namespace:PettingZoo.UI"
+                    xmlns:avalonedit="http://icsharpcode.net/sharpdevelop/avalonedit">
     <!-- Global styling -->
     <Style x:Key="WindowStyle" TargetType="{x:Type Window}">
         <Setter Property="Background" Value="{DynamicResource {x:Static SystemColors.ControlBrushKey}}"/>
@@ -83,10 +84,11 @@
     </Style>
 
 
-    <Style x:Key="Payload" TargetType="{x:Type TextBox}">
-        <Setter Property="AcceptsReturn" Value="True" />
-        <Setter Property="AcceptsTab" Value="True" />
-        <Setter Property="VerticalScrollBarVisibility" Value="Visible" />
+    <Style x:Key="Payload" TargetType="{x:Type avalonedit:TextEditor}">
         <Setter Property="FontFamily" Value="Consolas,Courier New" />
     </Style>
+
+    <Style x:Key="ControlBorder" TargetType="{x:Type Border}">
+        <Setter Property="BorderThickness" Value="1" />
+    </Style>
 </ResourceDictionary>

PettingZoo/UI/ErrorHighlightingTransformer.cs

@@ -0,0 +1,37 @@
+using System;
+using System.Windows.Media;
+using ICSharpCode.AvalonEdit.Document;
+using ICSharpCode.AvalonEdit.Rendering;
+
+namespace PettingZoo.UI
+{
+    public class ErrorHighlightingTransformer : DocumentColorizingTransformer
+    {
+        public Brush BackgroundBrush { get; set; }
+        public TextPosition? ErrorPosition { get; set; }
+
+
+        public ErrorHighlightingTransformer()
+        {
+            BackgroundBrush = new SolidColorBrush(Color.FromRgb(255, 230, 230));
+        }
+
+
+        protected override void ColorizeLine(DocumentLine line)
+        {
+            if (ErrorPosition == null)
+                return;
+
+            if (line.LineNumber != Math.Max(ErrorPosition.Value.Row, 1))
+                return;
+
+            var lineStartOffset = line.Offset;
+
+            ChangeLinePart(lineStartOffset, lineStartOffset + line.Length,
+                element =>
+                {
+                    element.BackgroundBrush = BackgroundBrush;
+                });
+        }
+    }
+}

PettingZoo/UI/ListBoxAutoScroll.cs

@@ -69,6 +69,8 @@ namespace PettingZoo.UI
         public void Dispose()
         {
             BindingOperations.ClearBinding(this, ItemsSourceProperty);
+
+            GC.SuppressFinalize(this);
         }
 
 

PettingZoo/UI/Main/MainWindow.xaml

@@ -79,7 +79,7 @@
         <StatusBar DockPanel.Dock="Bottom">
             <StatusBarItem>
                 <StackPanel Orientation="Horizontal">
-                    <Image Source="{svgc:SvgImage Source=/Images/Connecting.svg, AppName=PettingZoo}" Width="16" Height="16" Margin="4" Visibility="{Binding ConnectionStatusConnecting}" />
+                    <Image Source="{svgc:SvgImage Source=/Images/Busy.svg, AppName=PettingZoo}" Width="16" Height="16" Margin="4" Visibility="{Binding ConnectionStatusConnecting}" />
                     <Image Source="{svgc:SvgImage Source=/Images/Ok.svg, AppName=PettingZoo}" Width="16" Height="16" Margin="4" Visibility="{Binding ConnectionStatusOk}" />
                     <Image Source="{svgc:SvgImage Source=/Images/Error.svg, AppName=PettingZoo}" Width="16" Height="16" Margin="4" Visibility="{Binding ConnectionStatusError}" />
                     <TextBlock Text="{Binding ConnectionStatus}" VerticalAlignment="Center"/>

PettingZoo/UI/Main/MainWindow.xaml.cs

@@ -115,6 +115,8 @@ namespace PettingZoo.UI.Main
         private static T? GetParent<T>(object originalSource) where T : DependencyObject
         {
             var current = originalSource as DependencyObject;
+            if (current is not Visual)
+                return null;
 
             while (current != null)
             {

PettingZoo/UI/Tab/Publisher/PayloadEditorControl.xaml

@@ -17,15 +17,23 @@
             <RadioButton Content="JSON" Style="{StaticResource TypeSelection}" IsChecked="{Binding ContentTypeSelection, Converter={StaticResource EnumBooleanConverter}, ConverterParameter={x:Static publisher:PayloadEditorContentType.Json}}" />
             <RadioButton Content="Plain text" Style="{StaticResource TypeSelection}"  IsChecked="{Binding ContentTypeSelection, Converter={StaticResource EnumBooleanConverter}, ConverterParameter={x:Static publisher:PayloadEditorContentType.Plain}}" />
             <RadioButton Content="Other" Style="{StaticResource TypeSelection}"  IsChecked="{Binding ContentTypeSelection, Converter={StaticResource EnumBooleanConverter}, ConverterParameter={x:Static publisher:PayloadEditorContentType.Other}}" />
-            <TextBox Width="200" Text="{Binding ContentType, UpdateSourceTrigger=PropertyChanged}" />
+            <TextBox Name="TextBoxForBorder" Width="200" Text="{Binding ContentType, UpdateSourceTrigger=PropertyChanged}" />
         </StackPanel>
 
-        <StackPanel Orientation="Horizontal" DockPanel.Dock="Bottom" Visibility="{Binding JsonValidationVisibility}" Margin="0,8,0,0">
-            <Image Source="{svgc:SvgImage Source=/Images/Ok.svg, AppName=PettingZoo}" Width="16" Height="16" Margin="4" Visibility="{Binding JsonValidationOk}" />
-            <Image Source="{svgc:SvgImage Source=/Images/Error.svg, AppName=PettingZoo}" Width="16" Height="16" Margin="4" Visibility="{Binding JsonValidationError}" />
-            <TextBlock Text="{Binding JsonValidationMessage}" Margin="4" />
+        <StackPanel Orientation="Horizontal" DockPanel.Dock="Bottom" Visibility="{Binding ValidationVisibility}" Margin="0,8,0,0">
+            <Image Source="{svgc:SvgImage Source=/Images/Ok.svg, AppName=PettingZoo}" Width="16" Height="16" Margin="4" Visibility="{Binding ValidationOk}" />
+            <Image Source="{svgc:SvgImage Source=/Images/Error.svg, AppName=PettingZoo}" Width="16" Height="16" Margin="4" Visibility="{Binding ValidationError}" />
+            <Image Source="{svgc:SvgImage Source=/Images/Busy.svg, AppName=PettingZoo}" Width="16" Height="16" Margin="4" Visibility="{Binding ValidationValidating}" />
+            <TextBlock Text="{Binding ValidationMessage}" Margin="4" />
         </StackPanel>
 
-        <TextBox Text="{Binding Payload, UpdateSourceTrigger=PropertyChanged}" Style="{StaticResource Payload}" />
+        <Border Style="{StaticResource ControlBorder}" Name="EditorBorder">
+            <avalonedit:TextEditor
+            xmlns:avalonedit="http://icsharpcode.net/sharpdevelop/avalonedit"
+            Name="Editor"
+            SyntaxHighlighting="{Binding SyntaxHighlighting}"
+            Style="{StaticResource Payload}"
+        />
+        </Border>
     </DockPanel>
 </UserControl>

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

@@ -86,6 +86,9 @@ namespace PettingZoo.UI.Tab.Publisher
             }
         }
 
+
+        private readonly ErrorHighlightingTransformer errorHighlightingTransformer = new();
+
         public PayloadEditorControl()
         {
             // Keep the exposed properties in sync with the ViewModel
@@ -133,6 +136,42 @@ namespace PettingZoo.UI.Tab.Publisher
 
             InitializeComponent();
 
+            // I'm not sure how to get a standard control border, all I could find were workaround:
+            // https://social.msdn.microsoft.com/Forums/en-US/5e007497-8d5a-401d-ac5b-9e1356fe9b64/default-borderbrush-for-textbox-listbox-etc
+            // So I'll just copy it from another TextBox. I truly hate WPF some times for making standard things so complicated. </rant>
+            EditorBorder.BorderBrush = TextBoxForBorder.BorderBrush;
+
+            Editor.Options.IndentationSize = 2;
+            Editor.TextArea.TextView.LineTransformers.Add(errorHighlightingTransformer);
+
+            // Avalon doesn't play nice with bindings it seems:
+            // https://stackoverflow.com/questions/18964176/two-way-binding-to-avalonedit-document-text-using-mvvm
+            Editor.Document.Text = Payload;
+
+            Editor.TextChanged += (_, _) =>
+            {
+                Payload = Editor.Document.Text;
+            };
+
+
+            viewModel.PropertyChanged += (_, args) =>
+            {
+                if (args.PropertyName != nameof(viewModel.ValidationInfo))
+                    return;
+
+                Dispatcher.Invoke(() =>
+                {
+                    if (errorHighlightingTransformer.ErrorPosition == viewModel.ValidationInfo.ErrorPosition)
+                        return;
+
+                    errorHighlightingTransformer.ErrorPosition = viewModel.ValidationInfo.ErrorPosition;
+
+                    // TODO this can probably be optimized to only redraw the affected line
+                    Editor.TextArea.TextView.Redraw();
+                });
+            };
+
+
             // Setting the DataContext for the UserControl is a major PITA when binding the control's properties,
             // so I've moved the ViewModel one level down to get the best of both worlds...
             DataContextContainer.DataContext = viewModel;

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

@@ -88,20 +88,29 @@ namespace PettingZoo.UI.Tab.Publisher {
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to Invalid JSON: {0}.
+        ///   Looks up a localized string similar to Invalid: {0}.
         /// </summary>
-        internal static string JsonValidationError {
+        internal static string ValidationError {
             get {
-                return ResourceManager.GetString("JsonValidationError", resourceCulture);
+                return ResourceManager.GetString("ValidationError", resourceCulture);
             }
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to Valid JSON.
+        ///   Looks up a localized string similar to Valid.
         /// </summary>
-        internal static string JsonValidationOk {
+        internal static string ValidationOk {
             get {
-                return ResourceManager.GetString("JsonValidationOk", resourceCulture);
+                return ResourceManager.GetString("ValidationOk", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Validating....
+        /// </summary>
+        internal static string ValidationValidating {
+            get {
+                return ResourceManager.GetString("ValidationValidating", resourceCulture);
             }
         }
     }

PettingZoo/UI/Tab/Publisher/PayloadEditorStrings.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="ContentTypeJson" xml:space="preserve">
     <value>JSON</value>
@@ -126,10 +126,13 @@
   <data name="ContentTypePlain" xml:space="preserve">
     <value>Plain text</value>
   </data>
-  <data name="JsonValidationError" xml:space="preserve">
-    <value>Invalid JSON: {0}</value>
+  <data name="ValidationError" xml:space="preserve">
+    <value>Invalid: {0}</value>
   </data>
-  <data name="JsonValidationOk" xml:space="preserve">
-    <value>Valid JSON</value>
+  <data name="ValidationOk" xml:space="preserve">
+    <value>Valid</value>
+  </data>
+  <data name="ValidationValidating" xml:space="preserve">
+    <value>Validating...</value>
   </data>
 </root>

PettingZoo/UI/Tab/Publisher/PayloadEditorViewModel.cs

@@ -1,8 +1,9 @@
 using System;
 using System.ComponentModel;
 using System.Reactive.Linq;
-using System.Reactive.Subjects;
 using System.Windows;
+using ICSharpCode.AvalonEdit.Highlighting;
+using Newtonsoft.Json;
 using Newtonsoft.Json.Linq;
 
 namespace PettingZoo.UI.Tab.Publisher
@@ -15,6 +16,38 @@ namespace PettingZoo.UI.Tab.Publisher
     };
 
 
+    public enum ValidationStatus
+    {
+        NotSupported,
+        Validating,
+        Ok,
+        Error
+    }
+
+
+    public readonly struct ValidationInfo
+    {
+        public ValidationStatus Status { get; }
+        public string Message { get; }
+        public TextPosition? ErrorPosition { get; }
+
+
+        public ValidationInfo(ValidationStatus status, string? message = null, TextPosition? errorPosition = null)
+        {
+            Status = status;
+            Message = message ?? status switch
+            {
+                ValidationStatus.NotSupported => "",
+                ValidationStatus.Validating => PayloadEditorStrings.ValidationValidating,
+                ValidationStatus.Ok => PayloadEditorStrings.ValidationOk,
+                ValidationStatus.Error => throw new InvalidOperationException(@"Message required for Error validation status"),
+                _ => throw new ArgumentException(@"Unsupported validation status", nameof(status))
+            };
+            ErrorPosition = errorPosition;
+        }
+    }
+
+
     public class PayloadEditorViewModel : BaseViewModel
     {
         private const string ContentTypeJson = "application/json";
@@ -24,8 +57,7 @@ namespace PettingZoo.UI.Tab.Publisher
         private PayloadEditorContentType contentTypeSelection = PayloadEditorContentType.Json;
         private bool fixedJson;
 
-        private bool jsonValid = true;
-        private string jsonValidationMessage;
+        private ValidationInfo validationInfo = new(ValidationStatus.Ok);
 
         private string payload = "";
 
@@ -59,7 +91,7 @@ namespace PettingZoo.UI.Tab.Publisher
             get => contentTypeSelection;
             set
             {
-                if (!SetField(ref contentTypeSelection, value, otherPropertiesChanged: new [] { nameof(JsonValidationVisibility) }))
+                if (!SetField(ref contentTypeSelection, value, otherPropertiesChanged: new [] { nameof(ValidationVisibility), nameof(SyntaxHighlighting) }))
                     return;
 
                 ContentType = ContentTypeSelection switch
@@ -80,23 +112,22 @@ namespace PettingZoo.UI.Tab.Publisher
             set => SetField(ref fixedJson, value);
         }
 
-        public Visibility JsonValidationVisibility => ContentTypeSelection == PayloadEditorContentType.Json ? Visibility.Visible : Visibility.Collapsed;
-        public Visibility JsonValidationOk => JsonValid ? Visibility.Visible : Visibility.Collapsed;
-        public Visibility JsonValidationError => !JsonValid ? Visibility.Visible : Visibility.Collapsed;
 
-
-        public string JsonValidationMessage
+        public ValidationInfo ValidationInfo
         {
-            get => jsonValidationMessage;
-            private set => SetField(ref jsonValidationMessage, value);
+            get => validationInfo;
+            private set => SetField(ref validationInfo, value, otherPropertiesChanged: new[] { nameof(ValidationOk), nameof(ValidationError), nameof(ValidationValidating), nameof(ValidationMessage) });
         }
 
 
-        public bool JsonValid
-        {
-            get => jsonValid;
-            private set => SetField(ref jsonValid, value, otherPropertiesChanged: new[] { nameof(JsonValidationOk), nameof(JsonValidationError) });
-        }
+        public Visibility ValidationVisibility => ContentTypeSelection == PayloadEditorContentType.Json ? Visibility.Visible : Visibility.Collapsed;
+
+        public string ValidationMessage => ValidationInfo.Message;
+        
+        public Visibility ValidationOk => ValidationInfo.Status == ValidationStatus.Ok ? 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;
+
 
         public Visibility ContentTypeVisibility => FixedJson ? Visibility.Collapsed : Visibility.Visible;
 
@@ -108,26 +139,48 @@ namespace PettingZoo.UI.Tab.Publisher
         }
 
 
+        public IHighlightingDefinition? SyntaxHighlighting => ContentTypeSelection == PayloadEditorContentType.Json
+            ? HighlightingManager.Instance.GetDefinition(@"Json")
+            : null;
+
+
 
         public PayloadEditorViewModel()
         {
-            jsonValidationMessage = PayloadEditorStrings.JsonValidationOk;
-
-            Observable.FromEventPattern<PropertyChangedEventHandler, PropertyChangedEventArgs>(
+            var observable = Observable.FromEventPattern<PropertyChangedEventHandler, PropertyChangedEventArgs>(
                 h => PropertyChanged += h,
                 h => PropertyChanged -= h)
-                .Where(e => e.EventArgs.PropertyName == nameof(Payload))
+                .Where(e => e.EventArgs.PropertyName == nameof(Payload));
+
+            observable
+                .Subscribe(_ => ValidatingPayload());
+
+            observable
                 .Throttle(TimeSpan.FromMilliseconds(500))
                 .Subscribe(_ => ValidatePayload());
         }
 
 
+        private void ValidatingPayload()
+        {
+            if (ValidationInfo.Status == ValidationStatus.Validating)
+                return;
+
+            if (ContentTypeSelection != PayloadEditorContentType.Json)
+            {
+                ValidationInfo = new ValidationInfo(ValidationStatus.NotSupported);
+                return;
+            }
+
+            ValidationInfo = new ValidationInfo(ValidationStatus.Validating);
+        }
+
+
         private void ValidatePayload()
         {
             if (ContentTypeSelection != PayloadEditorContentType.Json)
             {
-                JsonValid = true;
-                JsonValidationMessage = PayloadEditorStrings.JsonValidationOk;
+                ValidationInfo = new ValidationInfo(ValidationStatus.NotSupported);
                 return;
             }
 
@@ -136,13 +189,15 @@ namespace PettingZoo.UI.Tab.Publisher
                 if (!string.IsNullOrEmpty(Payload))
                     JToken.Parse(Payload);
 
-                JsonValid = true;
-                JsonValidationMessage = PayloadEditorStrings.JsonValidationOk;
+                ValidationInfo = new ValidationInfo(ValidationStatus.Ok);
+            }
+            catch (JsonReaderException e)
+            {
+                ValidationInfo = new ValidationInfo(ValidationStatus.Error, e.Message, new TextPosition(e.LineNumber, e.LinePosition));
             }
             catch (Exception e)
             {
-                JsonValid = false;
-                JsonValidationMessage = string.Format(PayloadEditorStrings.JsonValidationError, e.Message);
+                ValidationInfo = new ValidationInfo(ValidationStatus.Error, e.Message);
             }
         }
     }

PettingZoo/UI/TextPosition.cs

@@ -0,0 +1,43 @@
+using System;
+
+namespace PettingZoo.UI
+{
+    public readonly struct TextPosition : IEquatable<TextPosition>
+    {
+        public int Row { get; }
+        public int Column { get; }
+
+
+        public TextPosition(int row, int column)
+        {
+            Row = row;
+            Column = column;
+        }
+
+
+        public bool Equals(TextPosition other)
+        {
+            return Row == other.Row && Column == other.Column;
+        }
+
+        public override bool Equals(object? obj)
+        {
+            return obj is TextPosition other && Equals(other);
+        }
+
+        public override int GetHashCode()
+        {
+            return HashCode.Combine(Row, Column);
+        }
+
+        public static bool operator ==(TextPosition left, TextPosition right)
+        {
+            return left.Equals(right);
+        }
+
+        public static bool operator !=(TextPosition left, TextPosition right)
+        {
+            return !(left == right);
+        }
+    }
+}