Question

我有一个没有标题栏的窗体。我想用鼠标拖动它。在互联网上搜索后，我找到了移动表格的代码：

protected override void WndProc(ref Message m)
{
    switch (m.Msg)
    {
        case 0x84:
            base.WndProc(ref m);
            if ((int)m.Result == 0x1)
                m.Result = (IntPtr)0x2;
            return;
    }
base.WndProc(ref m);
}

但是它有一个问题：它只在没有任何控件覆盖的表单区域上运行。例如，如果我使用标签或组合框，我无法通过点击它们来移动形式我该如何解决这个问题？

Answer 1

一种方法是像这样实施IMessageFilter。

public class MyForm : Form, IMessageFilter
{
    public const int WM_NCLBUTTONDOWN = 0xA1;
    public const int HT_CAPTION = 0x2;
    public const int WM_LBUTTONDOWN = 0x0201;

    [DllImportAttribute("user32.dll")]
    public static extern int SendMessage(IntPtr hWnd, int Msg, int wParam, int lParam);
    [DllImportAttribute("user32.dll")]
    public static extern bool ReleaseCapture();

    private HashSet<Control> controlsToMove = new HashSet<Control>();

    public MyForm()
    {
        Application.AddMessageFilter(this);

        controlsToMove.Add(this);
        controlsToMove.Add(this.myLabel);//Add whatever controls here you want to move the form when it is clicked and dragged
    }

    public bool PreFilterMessage(ref Message m)
    {
       if (m.Msg == WM_LBUTTONDOWN &&
            controlsToMove.Contains(Control.FromHandle(m.HWnd)))
        {
            ReleaseCapture();
            SendMessage(this.Handle, WM_NCLBUTTONDOWN, HT_CAPTION, 0);
            return true;
        }
        return false;
    }
}

Answer 2

这基本上就是你要做的事情：

Make a borderless form movable?

您可以将相同的代码添加到表单上其他控件的鼠标按下事件，以完成相同的操作。

Answer 3

当用户在窗体的lblMoveForm标签上按下鼠标时，将执行以下事件处理程序。

     // On left button, let the user drag the form.
private void lblMoveForm_MouseDown(object sender, MouseEventArgs e)
{
    if (e.Button == MouseButtons.Left)
    {
        // Release the mouse capture started by the mouse down.
        lblMoveForm.Capture = false; //select control

        // Create and send a WM_NCLBUTTONDOWN message.
        const int WM_NCLBUTTONDOWN = 0x00A1;
        const int HTCAPTION = 2;
        Message msg =
            Message.Create(this.Handle, WM_NCLBUTTONDOWN,
                new IntPtr(HTCAPTION), IntPtr.Zero);
        this.DefWndProc(ref msg);
    }
}

Answer 4

Make a borderless form movable?

public const int WM_NCLBUTTONDOWN = 0xA1;
public const int HT_CAPTION = 0x2;

[System.Runtime.InteropServices.DllImportAttribute("user32.dll")]
public static extern int SendMessage(IntPtr hWnd, int Msg, int wParam, int lParam);
[System.Runtime.InteropServices.DllImportAttribute("user32.dll")]
public static extern bool ReleaseCapture();

private void Form1_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
{     
    if (e.Button == MouseButtons.Left)
    {
        ReleaseCapture();
        SendMessage(Handle, WM_NCLBUTTONDOWN, HT_CAPTION, 0);
    }
}

没有标题栏的移动表单

4 个答案: