Selectioncolor 在 KeyPress 事件中不起作用

Question

我正在尝试在按下 Ctrl+Z 时更改某些文本的颜色，如下所示：

private void richTextBox1_KeyDown(object sender, KeyEventArgs e)
{
    if (e.KeyCode == Keys.Z && (e.Control))
    {
        if (undoList.Count > 0)
        {
            ignoreChange = true;
            richTextBox1.Text = undoList[undoList.Count - 1];
            //richTextBox1.Focus();
            richTextBox1.SelectionStart = 3;
            richTextBox1.SelectionLength = 2;

            richTextBox1.SelectionColor = Color.Green;
            undoList.RemoveAt(undoList.Count - 1);

            ignoreChange = false;
        }   
    }
}

但是，所选文本不会改变其颜色。它将保持突出显示。我在 Click 事件中加入了相同的逻辑并且它起作用了。此外，如果我取出 ichTextBox1.SelectionColor = Color.Green; 一切正常。不知道为什么。任何帮助，将不胜感激。

Answer 1

您想要处理命令键 (Control)，而这不会发生在标准的 KeyPress 事件中。为此，您必须覆盖表单上的 ProcessCmdKey 方法。

protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
{
    if (keyData == (Keys.Control|Keys.Z))
    {
        if (undoList.Count > 0)
        {
            ignoreChange = true;
            richTextBox1.Text = undoList[undoList.Count - 1];
            //richTextBox1.Focus();
            richTextBox1.SelectionStart = 3;
            richTextBox1.SelectionLength = 2;

            richTextBox1.SelectionColor = Color.Green;
            undoList.RemoveAt(undoList.Count - 1);

            ignoreChange = false;

            // Do not handle base method
            // which will revert the last action
            // that is changing the selection to green.
            return true;
        }
    }
    return base.ProcessCmdKey(ref msg, keyData);
}