如何更改富文本框wpf c#中选定的文本背景颜色

本文关键字：文本 背景 颜色 何更改 wpf | 更新日期: 2023-09-27 18:25:53

如何在RichTextBox控件中显示html文本？

实际上，我想在C#wpf中更改RichTextBox中所选的文本背景颜色。我尝试了这个代码，但它没有显示格式化的文本。

请帮帮我…提前谢谢！

void rtbTextEditor_SelectionChanged(object sender, RoutedEventArgs e)
{
    SelectionText = rtbTextEditor.Selection.Text.Trim();
    if (SelectionText != string.Empty)
    {
        if (VisualEditor.Document.Body != null)
        {
             //VisualEditor is web browser
             VisualEditor.Document.Body.InnerHtml = @"""<html><body><FONT style=""BACKGROUND-COLOR: #ffff00""><bold>""" + rtbTextEditor.Selection.Text + @"""</Bold></FONT></body></html>""";
             VisualEditor.Document.ExecCommand("SelectAll", false, null);
             rtbTextEditor.Document.Blocks.Add(new Paragraph(new Run(VisualEditor.Document.Body.InnerText.ToString())));
        }
    }
}

如何更改富文本框wpf c#中选定的文本背景颜色

private static TextPointer GetTextPointAt(TextPointer from, int pos)
  {
    TextPointer ret = from;
    int i = 0;
    while ((i < pos) && (ret != null))
    {
        if ((ret.GetPointerContext(LogicalDirection.Backward) == TextPointerContext.Text) || (ret.GetPointerContext(LogicalDirection.Backward) == TextPointerContext.None))
            i++;
        if (ret.GetPositionAtOffset(1, LogicalDirection.Forward) == null)
            return ret;
        ret = ret.GetPositionAtOffset(1, LogicalDirection.Forward);
    }
    return ret;
 }
 internal string Select(RichTextBox rtb, int offset, int length, Color color)
 {
    // Get text selection:
    TextSelection textRange = rtb.Selection;
    // Get text starting point:
    TextPointer start = rtb.Document.ContentStart;
    // Get begin and end requested:
    TextPointer startPos = GetTextPointAt(start, offset);
    TextPointer endPos = GetTextPointAt(start, offset + length);
    // New selection of text:
    textRange.Select(startPos, endPos);
    // Apply property to the selection:
    textRange.ApplyPropertyValue(TextElement.BackgroundProperty, new SolidColorBrush(color));
    // Return selection text:
    return rtb.Selection.Text;
 }

然后以这种方式使用它（我从红色的第一个字符到第五个字符进行选择）：

this.Select(this.myRichTextBox, 0, 5, Colors.Red);
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