Improve MetricTile tooltip rendering and update logic

Refactored MetricTile to remove the hidden TextBox and instead update the tooltip TextBlock directly when the Tooltip property changes or the control loads. Tooltips now support basic HTML formatting (<b>, <i>, <br>) and handle malformed HTML gracefully. The control now listens for DataContext and property changes to keep tooltips up-to-date.

Author: Ariel Silahian

UserControls/MetricTile.xaml

@@ -3,7 +3,9 @@
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
              xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
-             xmlns:local="clr-namespace:VisualHFT.Converters" xmlns:viewmodel="clr-namespace:VisualHFT.ViewModel" d:DataContext="{d:DesignInstance Type=viewmodel:vmTile}"
+             xmlns:local="clr-namespace:VisualHFT.Converters" 
+             xmlns:viewmodel="clr-namespace:VisualHFT.ViewModel" 
+             d:DataContext="{d:DesignInstance Type=viewmodel:vmTile}"
              mc:Ignorable="d" 
             TextElement.Foreground="{DynamicResource MaterialDesignBody}"
             TextElement.FontWeight="Regular"
@@ -12,9 +14,8 @@
             TextOptions.TextRenderingMode="Auto"
             Background="{DynamicResource MaterialDesignPaper}"
             FontFamily="{StaticResource MaterialDesignFont}"
-
-             
-             d:DesignHeight="250" d:DesignWidth="300">
+            d:DesignHeight="250" d:DesignWidth="300"
+            Loaded="UserControl_Loaded">
     <UserControl.Resources>
         <ResourceDictionary>
             <ResourceDictionary.MergedDictionaries>
@@ -33,7 +34,6 @@
                 <Grid.ToolTip>
                     <TextBlock x:Name="txtToolTip" TextWrapping="Wrap" Width="300" />
                 </Grid.ToolTip>
-                <TextBox Visibility="Collapsed" Text="{Binding Tooltip, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" TextChanged="TextBox_TextChanged" />
 
                 <Viewbox Grid.Row="0" HorizontalAlignment="Center" VerticalAlignment="Center" Stretch="Uniform" Visibility="{Binding ValueVisibility}">
                     <TextBlock Text="{Binding Value}" Foreground="{Binding ValueColor}" ToolTip="{Binding ValueTooltip}" VerticalAlignment="Stretch" HorizontalAlignment="Stretch" Margin="2 0 2 0"/>

UserControls/MetricTile.xaml.cs

@@ -1,7 +1,9 @@
 using System.Text.RegularExpressions;
+using System.Windows;
 using System.Windows.Controls;
 using System.Windows.Documents;
 using System.Xml;
+
 namespace VisualHFT.UserControls
 {
     /// <summary>
@@ -12,59 +14,110 @@ public partial class MetricTile : UserControl
         public MetricTile()
         {
             InitializeComponent();
+
+            // Subscribe to DataContext changes to update tooltip
+            DataContextChanged += MetricTile_DataContextChanged;
+        }
+
+        private void MetricTile_DataContextChanged(object sender, DependencyPropertyChangedEventArgs e)
+        {
+            if (e.NewValue is VisualHFT.ViewModel.vmTile tile)
+            {
+                // Subscribe to property changes
+                tile.PropertyChanged += Tile_PropertyChanged;
+
+                // Update tooltip immediately with current value
+                UpdateTooltip(tile.Tooltip);
+            }
+
+            if (e.OldValue is VisualHFT.ViewModel.vmTile oldTile)
+            {
+                // Unsubscribe from old tile
+                oldTile.PropertyChanged -= Tile_PropertyChanged;
+            }
         }
 
-        private void TextBox_TextChanged(object sender, TextChangedEventArgs e)
+        private void Tile_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
         {
-            TextBox textBox = sender as TextBox;
-            if (textBox != null)
+            if (e.PropertyName == nameof(VisualHFT.ViewModel.vmTile.Tooltip))
             {
-                ConvertHtmlToTextBlock(textBox.Text, txtToolTip);
+                var tile = sender as VisualHFT.ViewModel.vmTile;
+                UpdateTooltip(tile?.Tooltip);
             }
         }
+
+        private void UserControl_Loaded(object sender, RoutedEventArgs e)
+        {
+            // Update tooltip when control loads
+            if (DataContext is VisualHFT.ViewModel.vmTile tile)
+            {
+                UpdateTooltip(tile.Tooltip);
+            }
+        }
+
+        private void UpdateTooltip(string htmlText)
+        {
+            if (string.IsNullOrEmpty(htmlText))
+            {
+                txtToolTip.Inlines.Clear();
+                return;
+            }
+
+            ConvertHtmlToTextBlock(htmlText, txtToolTip);
+        }
+
         public TextBlock ConvertHtmlToTextBlock(string htmlText, TextBlock textBlock)
         {
             htmlText = XmlEscapeAmpersands(htmlText);
 
+            textBlock.Inlines.Clear(); // Clear existing inlines
             textBlock.TextWrapping = System.Windows.TextWrapping.Wrap;
             textBlock.Width = 500;
 
-            XmlDocument doc = new XmlDocument();
-            doc.LoadXml("<root>" + htmlText + "</root>");
-
-            foreach (XmlNode node in doc.DocumentElement.ChildNodes)
+            try
             {
-                if (node.NodeType == XmlNodeType.Text)
-                {
-                    textBlock.Inlines.Add(new Run(node.Value));
-                }
-                else if (node.Name == "br")
-                {
-                    textBlock.Inlines.Add(new LineBreak());
-                }
-                else if (node.Name == "b")
-                {
-                    Run run = new Run(node.InnerText);
-                    run.FontWeight = System.Windows.FontWeights.Bold;
-                    textBlock.Inlines.Add(run);
-                }
-                else if (node.Name == "i")
+                XmlDocument doc = new XmlDocument();
+                doc.LoadXml("<root>" + htmlText + "</root>");
+
+                foreach (XmlNode node in doc.DocumentElement.ChildNodes)
                 {
-                    Run run = new Run(node.InnerText);
-                    run.FontStyle = System.Windows.FontStyles.Italic;
-                    textBlock.Inlines.Add(run);
+                    if (node.NodeType == XmlNodeType.Text)
+                    {
+                        textBlock.Inlines.Add(new Run(node.Value));
+                    }
+                    else if (node.Name == "br")
+                    {
+                        textBlock.Inlines.Add(new LineBreak());
+                    }
+                    else if (node.Name == "b")
+                    {
+                        Run run = new Run(node.InnerText);
+                        run.FontWeight = System.Windows.FontWeights.Bold;
+                        textBlock.Inlines.Add(run);
+                    }
+                    else if (node.Name == "i")
+                    {
+                        Run run = new Run(node.InnerText);
+                        run.FontStyle = System.Windows.FontStyles.Italic;
+                        textBlock.Inlines.Add(run);
+                    }
+                    // Add more formatting cases as needed
                 }
-                // Add more formatting cases as needed
+            }
+            catch (XmlException)
+            {
+                // If HTML parsing fails, show raw text
+                textBlock.Inlines.Add(new Run(htmlText));
             }
 
             return textBlock;
         }
+
         private static string XmlEscapeAmpersands(string s)
         {
             if (string.IsNullOrEmpty(s)) return s;
             // Replace & not starting a valid entity with &amp;
             return Regex.Replace(s, "&(?!(?:#\\d+|#x[0-9A-Fa-f]+|[A-Za-z][A-Za-z0-9]*);)", "&amp;");
         }
-
     }
 }