禁用Richtextbox上的平滑滚动

Question

我有一个标签,根据RichTextBox上的文字标记行号.我已经联系了Vscroll的事件来处理标签.

private void rtbLogicCode_VScroll(object sender, EventArgs e)
{
    Point pt = new Point(0, 1);
    int firstIndex = rtbLogicCode.GetCharIndexFromPosition(pt);
    int firstLine = rtbLogicCode.GetLineFromCharIndex(firstIndex);

    pt.X = ClientRectangle.Width;
    pt.Y = ClientRectangle.Height;
    int lastIndex = rtbLogicCode.GetCharIndexFromPosition(pt);
    int lastLine = rtbLogicCode.GetLineFromCharIndex(lastIndex);

    // Small correction
    if (rtbLogicCode.Text.EndsWith("\n"))
        lastLine++;

    labelLogicCode.ResetText();
    LabelLineNum(firstLine+1,lastLine);
}
#endregion

private void LabelLineNum(int startNum, int lastNum)
{
    labelLogicCode.Font = UIConstant.DDCLogicCodeFont;
    for (int i = startNum; i < lastNum; i++)
    {
        labelLogicCode.Text += i + Environment.NewLine;
    }
}

除了RichTextBox使用平滑滚动功能之外,一切似乎都能正常工作,在许多情况下用户没有滚动到下一行的情况下,这会使我的行编号搞砸.这会导致行号与RichTextBox上显示的实际文本不同步.

最后,我需要禁用smoothscrolling功能来完成此任务.我被告知你可以覆盖RichTextBox的postMessage API来禁用所提到的功能,但在搜索了很多文档之后,我找不到任何好的文档.

我将非常感谢有关如何禁用smoothscrolling功能的尽可能详细的解决方案.谢谢.

Answer 1

这是Microsoft 的一个VB示例,建议您需要拦截WM_MOUSEWHEEL消息.

这是C#中的快速原型:

class MyRichTextBox : RichTextBox {

    [DllImport("user32.dll")]
    public static extern IntPtr SendMessage(
          IntPtr hWnd,      // handle to destination window
          uint Msg,       // message
          IntPtr wParam,  // first message parameter
          IntPtr lParam   // second message parameter
    );

    const uint WM_MOUSEWHEEL = 0x20A;
    const uint WM_VSCROLL = 0x115;
    const uint SB_LINEUP = 0;
    const uint SB_LINEDOWN = 1;
    const uint SB_THUMBTRACK = 5;

    private void Intercept(ref Message m) {
        int delta = (int)m.WParam >> 16 & 0xFF;
        if((delta >> 7) == 1) {
            SendMessage(m.HWnd, WM_VSCROLL, (IntPtr)SB_LINEDOWN, (IntPtr)0);
        } else {
            SendMessage(m.HWnd, WM_VSCROLL, (IntPtr)SB_LINEUP, (IntPtr)0);
        }
    }

    protected override void WndProc(ref Message m) {
        switch((uint)m.Msg) {
            case WM_MOUSEWHEEL:
                Intercept(ref m);
                break;
            case WM_VSCROLL:
                if(((uint)m.WParam & 0xFF) == SB_THUMBTRACK) {
                    Intercept(ref m);
                } else {
                    base.WndProc(ref m);
                }
                break;
            default:
                base.WndProc(ref m);
                break;
        }
    }
}