Question

我是VB应用程序的新手。我的基本背景是C.我刚刚安装了VB并从谷歌和微软帮助中心学习东西。我正在玩我正在做的事情但是我被困在一个点，那就是在富文本框中。有没有办法在VB中跟踪Rich文本框文本？因此，当用户点击新行（即输入）时，我可以附加一些文本，并在他按下退格键时执行一些任务。我如何跟踪richtextbox。？

我找到了

      stringer = RichTextBox1.Lines(0)  to read lines
      & vbNewLine  for new line

我如何阅读该用户在vb富文本框中点击新行字符或退格键？因为在C我以前做过这样的事情

      if a = 13; \\ ascii for new line and 8 for backspace

我只是想在用户点击新行时执行某项任务，但我无法弄清楚要做什么条件。在VB或其Windows应用程序上的vb和文档的任何良好链接都会受到赞赏。提前谢谢

Answer 1

您需要链接到RichTextBox的KeyDown事件。在此事件中，您可以修改当前行的文本。用于向行添加文本的示例代码为：

Private Sub RichTextBox1_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles RichTextBox1.KeyDown
    Dim textToAdd As String = " ** text to add **"

    'Fire when the Enter key is pressed
    If e.KeyCode = Keys.Enter Then
        'Get the current cursor position
        Dim cursorPos As Integer = RichTextBox1.SelectionStart

        'Get the current line index
        Dim index As Integer = RichTextBox1.GetLineFromCharIndex(cursorPos)

        'Load all the lines into a string array
        'This has to be done since editing via RichTextBox1.Lines(index) = "" doesn't always work
        Dim lines() As String = RichTextBox1.Lines

        'Add the text to the correct line
        lines(index) &= textToAdd

        'Assign the text back to the RichTextBox
        RichTextBox1.Lines = lines

        'Move the cursor to the correct position
        RichTextBox1.SelectionStart = cursorPos + textToAdd.Length
    End If
End Sub

Answer 2

您需要做的就是检查是否按下了Enter或BackSpace键，如下所示：

Private Sub RichTextBox1_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles RichTextBox1.KeyDown

    Select Case e.KeyCode
            Case Keys.Enter
                'Do stuff when Enter was pressed
            Case Keys.Back
                'Do stuff when BackSpace was pressed
        End Select
    End Sub

请注意，Select Case与C中的开关相同。

跟踪richtext框文本？

2 个答案: