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[英]Prevent delete/backspace of InlineUIContainers in RichTextBox (WPF)
[英]How to check if I'm deleting (Backspace, Delete or 'Cut') a UIElement in a RichTextBox?
我有一个RichTextBox
必须包含一些按钮,当用户在其中编辑内容时应该正确删除(处理)这些按钮。 我能够检查我是否正在删除(Backspace、Delete 或 Cut)文本(字符),但不是<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; */
}
}
我知道start.GetTextInRun
仅获取文本,并且在退格按钮时得到值“”( null
)。 但我也尝试过start.GetAdjacentElement
,但我无法在相同条件下成功检索<Button>
。
我刚刚(大致)复制了上面的代码,当我将 cursor 放在添加的按钮之后并按 Backspace 时,即使没有 PreviewKeyDown 代码,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>
和背后的代码......
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;
}
}
}
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