Question

我在WPF中有一个RichTextBox（Name="txtGoTo"），我只需要第一个用红色着色的字符（其余字符用默认的黑色）。

这是我尝试过的（在网上获得），但它不起作用：

    Dim rtb As RichTextBox = txtGoTo
    Dim Text As String = New TextRange(rtb.Document.ContentStart, rtb.Document.ContentEnd).Text

    If Not String.IsNullOrEmpty(Text) Then

        Dim RangeAisle As TextPointer = rtb.Document.ContentStart
        Dim RangeShelf As TextPointer = rtb.Document.ContentStart.GetPositionAtOffset(1)

        Dim tr As New TextRange(RangeAisle, RangeShelf)
        tr.ApplyPropertyValue(RichTextBox.ForegroundProperty, Brushes.Red)
    End If

Answer 1

您的问题是rtb.Document.ContentStart.GetPositionAtOffset(1)没有返回首字母。它更像是3

的索引

下面的代码将获得第一个字母的位置并更改为红色。

Dim position As TextPointer = rtb.Document.ContentStart
While position IsNot Nothing
    If position.GetPointerContext(LogicalDirection.Forward) = TextPointerContext.Text Then
        Dim start As TextPointer = position.GetPositionAtOffset(0, LogicalDirection.Forward)
        Dim [end] As TextPointer = position.GetPositionAtOffset(1, LogicalDirection.Backward)
        New TextRange(start, [end]).ApplyPropertyValue(TextElement.ForegroundProperty, Brushes.Red)
        Exit While
    End If
    position = position.GetNextContextPosition(LogicalDirection.Forward)
End While

RichTextBox：第一个字符的颜色不同

1 个答案: