在WPF RichTextBox中的文本范围上设置工具提示

Question

I am trying to set a tooltip on an arbitrary range of text on a richtextbox. Is this possible? If so how would I do it eg by passing in parameters "from" and "to" as (int) indexes.

Thanks

Answer 1

You could use the following as a starting point:

1. Add a reference to System.Windows.Interactivity .

2. Add the following classes to your project:

    public class TextRangeToolTip { public int StartPosition { get; set; } public int Length { get; set; } public object ToolTip { get; set; } internal bool IsInRange(int position) { return this.StartPosition <= position && position < this.StartPosition + this.Length; } } public class TextRangeToolTipCollection : ObservableCollection<TextRangeToolTip> {} [ContentProperty("Ranges")] public class ToolTipBehavior : Behavior<RichTextBox> { private const int ToolTipHideMouseDelta = 9; public static readonly DependencyProperty RangesProperty = DependencyProperty.Register("Ranges", typeof(TextRangeToolTipCollection), typeof (ToolTipBehavior), new PropertyMetadata(OnRangesChanged)); private readonly DispatcherTimer timer; private readonly ToolTip toolTip; private Point lastMousePosition; public TextRangeToolTipCollection Ranges { get { return (TextRangeToolTipCollection)this.GetValue(RangesProperty) ?? (this.Ranges = new TextRangeToolTipCollection()); } set { this.SetValue(RangesProperty, value); } } public ToolTipBehavior() { this.Ranges = new TextRangeToolTipCollection(); this.timer = new DispatcherTimer(); this.timer.Tick += this.TimerOnTick; this.timer.Interval = TimeSpan.FromSeconds(1); this.toolTip = new ToolTip {Placement = PlacementMode.Relative}; } protected override void OnAttached() { this.AssociatedObject.ToolTip = this.toolTip; this.toolTip.PlacementTarget = this.AssociatedObject; ToolTipService.SetIsEnabled(this.AssociatedObject, false); this.AssociatedObject.MouseMove += this.AssociatedObjectOnMouseMove; } protected override void OnDetaching() { this.timer.Stop(); this.toolTip.PlacementTarget = null; this.AssociatedObject.ToolTip = null; this.AssociatedObject.ClearValue(ToolTipService.IsEnabledProperty); this.AssociatedObject.MouseMove -= this.AssociatedObjectOnMouseMove; } private void AssociatedObjectOnMouseMove(object sender, MouseEventArgs mouseEventArgs) { Point currentMousePosition = mouseEventArgs.GetPosition(this.AssociatedObject); if (this.AssociatedObject.IsMouseCaptured) { Vector delta = currentMousePosition - this.lastMousePosition; if (delta.X*delta.X + delta.Y*delta.Y <= ToolTipHideMouseDelta) { this.toolTip.HorizontalOffset = currentMousePosition.X + 10; this.toolTip.VerticalOffset = currentMousePosition.Y + 10; return; } this.AssociatedObject.ReleaseMouseCapture(); this.toolTip.IsOpen = false; } if (this.AssociatedObject.IsMouseOver) { this.lastMousePosition = currentMousePosition; this.timer.Stop(); this.timer.Start(); } } private static void OnRangesChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) { ((ToolTipBehavior) d).OnRangesChanged((IEnumerable<TextRangeToolTip>) e.OldValue, (IEnumerable<TextRangeToolTip>) e.NewValue); } private void OnRangesChanged(IEnumerable<TextRangeToolTip> oldRanges, IEnumerable<TextRangeToolTip> newRanges) { var oldObservable = oldRanges as INotifyCollectionChanged; if (oldObservable != null) { CollectionChangedEventManager.RemoveHandler(oldObservable, this.OnRangesCollectionChanged); } var newObservable = newRanges as INotifyCollectionChanged; if (newObservable != null) { CollectionChangedEventManager.AddHandler(newObservable, this.OnRangesCollectionChanged); } this.UpdateToolTip(); } private void OnRangesCollectionChanged( object sender, NotifyCollectionChangedEventArgs notifyCollectionChangedEventArgs) { this.UpdateToolTip(); } private bool SetToolTipData() { if (this.Ranges == null) { return false; } TextPointer pointer = this.AssociatedObject.GetPositionFromPoint(this.lastMousePosition, false); if (pointer == null) { return false; } int position = this.AssociatedObject.Document.ContentStart.GetOffsetToPosition(pointer); TextRangeToolTip matchingRange = this.Ranges.FirstOrDefault(r => r.IsInRange(position)); if (matchingRange == null) { return false; } this.toolTip.Content = matchingRange.ToolTip; return true; } private void TimerOnTick(object sender, EventArgs eventArgs) { this.timer.Stop(); if (this.AssociatedObject.IsMouseOver && this.SetToolTipData()) { this.toolTip.IsOpen = true; this.AssociatedObject.CaptureMouse(); } } private void UpdateToolTip() { if (this.AssociatedObject != null && this.AssociatedObject.IsMouseCaptured && !this.SetToolTipData()) { this.toolTip.IsOpen = false; this.AssociatedObject.ReleaseMouseCapture(); } } } 

3. Use it on your RichTextBox like this:

    <RichTextBox> <i:Interaction.Behaviors> <myapp:ToolTipBehavior> <myapp:TextRangeToolTip StartPosition="10" Length="4" ToolTip="some" /> <myapp:TextRangeToolTip StartPosition="15" Length="4" ToolTip="text" /> </myapp:ToolTipBehavior> </i:Interaction.Behaviors> <FlowDocument> <Paragraph>This is some text. This is some other text.</Paragraph> </FlowDocument> </RichTextBox> 

   Alternatively, you can bind a TextRangeToolTipCollection to the Ranges property like this:

    <RichTextBox Document="{Binding Document}"> <i:Interaction.Behaviors> <myapp:ToolTipBehavior Ranges="{Binding RangeToolTips}" /> </i:Interaction.Behaviors> </RichTextBox> 

Getting the positions right is a bit tricky, because WPF counts symbols, not characters. You could extend the TextRangeToolTip class to have properties of type TextPointer or TextRange and construct it using your FlowDocument instance.