add TextBlockAttach

src/Shared/HandyControl_Shared/Controls/Attach/TextBlockAttach.cs

@@ -0,0 +1,53 @@
+using System.Windows;
+using System.Windows.Controls;
+using HandyControl.Data;
+
+namespace HandyControl.Controls
+{
+    public class TextBlockAttach
+    {
+        public static readonly DependencyProperty AutoTooltipProperty = DependencyProperty.RegisterAttached(
+            "AutoTooltip", typeof(bool), typeof(TextBlockAttach), new PropertyMetadata(ValueBoxes.FalseBox, OnAutoTooltipChanged));
+
+        private static void OnAutoTooltipChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
+        {
+            if (d is TextBlock ctl)
+            {
+                if ((bool)e.NewValue)
+                {
+                    ctl.TextTrimming = TextTrimming.WordEllipsis;
+                    UpdateTooltip(ctl);
+                    ctl.SizeChanged += TextBlock_SizeChanged;
+                }
+                else
+                {
+                    ctl.ClearValue(TextBlock.TextTrimmingProperty);
+                    ctl.SizeChanged -= TextBlock_SizeChanged;
+                }
+            }
+        }
+
+        public static void SetAutoTooltip(DependencyObject element, bool value)
+            => element.SetValue(AutoTooltipProperty, value);
+
+        public static bool GetAutoTooltip(DependencyObject element)
+            => (bool) element.GetValue(AutoTooltipProperty);
+
+        private static void TextBlock_SizeChanged(object sender, SizeChangedEventArgs e)
+        {
+            if (sender is TextBlock textBlock)
+            {
+                UpdateTooltip(textBlock);
+            }
+        }
+
+        private static void UpdateTooltip(TextBlock textBlock)
+        {
+            textBlock.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity));
+            var width = textBlock.DesiredSize.Width - textBlock.Margin.Left - textBlock.Margin.Right;
+
+            ToolTipService.SetToolTip(textBlock,
+                textBlock.RenderSize.Width > width || textBlock.ActualWidth < width ? textBlock.Text : null);
+        }
+    }
+}