捕获CTRL + V或粘贴到.NET中的文本框中

Question

VB.NET 2010 - 我有一个RichTextbox,用户可以在其中手动输入数据或从其他来源复制/粘贴.数据完成后,他会点击并突出显示几个关键词.我的问题是,如果他从其他来源复制/粘贴,格式也会被复制.好吧,有时外部源有一个白色字体,我的文本框有一个白色背景,所以看起来他没有粘贴,他一次又一次地做.

我正在寻找的是一种拦截粘贴操作到文本框的方法,这样我就可以将该文本粘贴为纯ASCII,而无需格式化.

在使用KeyDown进行实验后进行编辑

Private Sub txtRch_KeyDown(sender As Object, e As System.Windows.Forms.KeyEventArgs) Handles txtRch.KeyDown
    If e.Modifiers = Keys.Control AndAlso e.KeyCode = Keys.V Then
        With txtRch
            Dim i As Integer = .SelectionStart          'cache the current position
            .Select(0, i)                               'select text from start to current position
            Dim s As String = .SelectedText             'copy that text to a variable
            .Select(i, .TextLength)                     'now select text from current position to end
            Dim t As String = .SelectedText             'copy that text to a variable
            Dim u As String = s & Clipboard.GetText(TextDataFormat.UnicodeText) & t 'now concatenate the first chunk, the new text, and the last chunk
            .Clear()                                    'clear the textbox
            .Text = u                                   'paste the new text back into textbox
            .SelectionStart = i                         'put cursor back to cached position
        End With

        'the event has been handled manually
        e.Handled = True
    End If
End Sub

这似乎工作,我的所有文本都保留,其全部ASCII.我想如果我想更进一步,我也可以采用我的RichTextbox的字体和前景,选择所有文本,然后将字体和前景分配给选择.

Answer 1

在大多数情况下,检查KeyDown事件应该足够好,并使用临时RichTextBox来修改传入的文本:

Private Sub RichTextBox1_KeyDown(sender As Object, e As KeyEventArgs) _
                                 Handles RichTextBox1.KeyDown
  If e.Modifiers = Keys.Control AndAlso e.KeyCode = Keys.V Then

    Using box As New RichTextBox
      box.SelectAll()
      box.SelectedRtf = Clipboard.GetText(TextDataFormat.Rtf)
      box.SelectAll()
      box.SelectionBackColor = Color.White
      box.SelectionColor = Color.Black
      RichTextBox1.SelectedRtf = box.SelectedRtf
   End Using

   e.Handled = True
  End If
End Sub

注意:缺少任何错误检查.