c# - 如何检查我是否正在删除(退格键、删除或 'Cut' )RichTextBox 中的 UIElement？

Question

我有一个 RichTextBox它必须包含一些按钮，当用户在其中编辑内容时应正确删除(处理)这些按钮。我可以检查我是否正在删除(退格键、删除或剪切)文本(字符)而不是 <Button>控制元素。

附上我用过的代码:

XAML:

<RichTextBox x:Name="tRTB"
             HorizontalAlignment="Left"
             Keyboard.PreviewKeyDown="tRTB_PreviewKeyDown"
             PreviewTextInput="tRTB_PreviewTextInput">
   <local:EnabledFlowDocument x:Name="tFD">
      <Paragraph x:Name="tP"/>                 
   </local:EnabledFlowDocument>
</RichTextBox>

C#:

public void AppendNewButton(int i)
{
    Button addB = new Button();
    addB.Content = i;
    addB.HorizontalAlignment = HorizontalAlignment.Left;

    tP.Inlines.Add(addB);
    tP.Inlines.Add("Bk" + i.ToString()); //appends a button and text in RTB
}

和事件:

private void tRTB_PreviewKeyDown(object sender, KeyEventArgs e)
{
    if (e.Key == Key.Back)
    {
        var start = tRTB.CaretPosition;
        var t = start.GetTextInRun(LogicalDirection.Backward);
        var end = start.GetNextContextPosition(LogicalDirection.Backward);
        var t1 = end.GetTextInRun(LogicalDirection.Backward);

        tRTB.Selection.Select(start, end);
        tRTB.Selection.ApplyPropertyValue(TextElement.ForegroundProperty, Brushes.Black);
        tRTB.Selection.Select(start, start);

        //should handle deletion of button here
        /* if (button is before cursor) */
        /* e.Handled=true; */
    }
}

据我所知，start.GetTextInRun仅获取文本，退格按钮时我得到值“”( null )。但我试过了 start.GetAdjacentElement同样，但我无法成功检索 <Button>在相同的条件下。

Answer 1

我只是(粗略地)复制了您上面的代码，当我将光标放在添加的按钮之后并按下退格键时，即使没有您的 PreviewKeyDown 代码，该按钮也会从 RichTextBox 中删除。所以我很困惑，因为答案似乎就是你根本不需要做任何事情。这是我的代码:

<Window x:Class="WpfApplication4.MainWindow"
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  Title="MainWindow" Height="350" Width="525">
  <Grid>
    <RichTextBox 
      x:Name="tRTB"
      HorizontalAlignment="Left"
      Keyboard.PreviewKeyDown="tRTB_PreviewKeyDown">
    </RichTextBox>
  </Grid>
</Window>

以及背后的代码...

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
    }

    public void AppendNewButton(int i)
    {
        Button addB = new Button();
        addB.Content = i;
        addB.HorizontalAlignment = HorizontalAlignment.Left;

        var insertionPosition = tRTB.CaretPosition.GetInsertionPosition(LogicalDirection.Forward);

        var inline = new InlineUIContainer(addB);
        insertionPosition.Paragraph.Inlines.InsertAfter(
            (Inline)insertionPosition.Parent,
            inline);

        tRTB.CaretPosition = tRTB.CaretPosition.GetNextInsertionPosition(LogicalDirection.Forward);
    }

    public void tRTB_PreviewKeyDown(object sender, KeyEventArgs e)
    {
        if (e.Key == Key.B)
        {
            AppendNewButton(7);
            e.Handled = true;
        }
    }
}