将系统默认上下文菜单添加到无边框 Windows 窗体

Question

我从我的 Windows 窗体中删除了默认边框并创建了我自己的标题，我想提供与默认窗体相同的功能。

其中之一是鼠标右键单击时显示的上下文菜单：

是否有可能将其分配给我的服装标题？

如果要贴代码我更喜欢vb，c#也可以。

Answer 1

默认情况下，无边框表单没有系统菜单。您应该首先通过在CreateParams 中添加WS_SYSMENU 样式来启用表单的系统菜单。然后你可以发送WM_POPUPSYSTEMMENU到OnMouseDown中的窗口。

C#

然后设置this.FormBorderStyle = Windows.Forms.FormBorderStyle.None;：

private const int WS_SYSMENU = 0x80000;
private const int WS_MINIMIZEBOX = 0x20000;
private const int WS_MAXIMIZEBOX = 0x10000;
protected override CreateParams CreateParams
{
    get
    {
        CreateParams p = base.CreateParams;
        p.Style = WS_SYSMENU | WS_MINIMIZEBOX | WS_MAXIMIZEBOX;
        return p;
    }
}

[DllImport("user32.dll")]
private static extern IntPtr SendMessage(IntPtr hWnd, int msg,
    IntPtr wParam, IntPtr lParam);
private const int WM_POPUPSYSTEMMENU = 0x313;
protected override void OnMouseDown(MouseEventArgs e)
{
    base.OnMouseDown(e);
    if (e.Button == System.Windows.Forms.MouseButtons.Right)
    {
        var p = MousePosition.X + (MousePosition.Y * 0x10000);
        SendMessage(this.Handle, WM_POPUPSYSTEMMENU, (IntPtr)0, (IntPtr)p);
    }
}

VB.NET

然后设置Me.FormBorderStyle = Windows.Forms.FormBorderStyle.None：

Private Const WS_SYSMENU As Integer = &H80000
Private Const WS_MINIMIZEBOX As Integer = &H20000
Private Const WS_MAXIMIZEBOX As Integer = &H10000
Protected Overrides ReadOnly Property CreateParams As System.Windows.Forms.CreateParams
    Get
        Dim p = MyBase.CreateParams
        p.Style = WS_SYSMENU + WS_MINIMIZEBOX + WS_MAXIMIZEBOX
        Return p
    End Get
End Property

<DllImport("user32.dll")>
Private Shared Function SendMessage(ByVal hWnd As IntPtr, ByVal msg As Integer, _
    ByVal wParam As IntPtr, ByVal lParam As IntPtr) As IntPtr
End Function
Private Const WM_POPUPSYSTEMMENU As Integer = &H313
Protected Overrides Sub OnMouseDown(ByVal e As System.Windows.Forms.MouseEventArgs)
    MyBase.OnMouseDown(e)
    If e.Button = MouseButtons.Right Then
        Dim p = MousePosition.X + (MousePosition.Y * &H10000)
        SendMessage(Me.Handle, WM_POPUPSYSTEMMENU, 0, p)
    End If
End Sub

注意

WM_POPUPSYSTEMMENU 未记录但完全可以正常工作。如果您想使用文档化的方式，您可以使用GetSystemMenu 获取系统菜单，然后使用TrackPopupMenu 显示它并使用SendMessage 执行返回的命令。您可以声明：

Private Const TPM_LEFTBUTTON As Integer = &H0
Private Const TPM_RIGHTBUTTON As Integer = &H2
Private Const TPM_RETURNCMD As Integer = &H100
Private Const WM_SYSCOMMAND As Integer = &H112
<DllImport("user32.dll")> _
Private Shared Function GetSystemMenu(ByVal hWnd As IntPtr, _
    ByVal bRevert As Boolean) As IntPtr
End Function
<DllImport("user32.dll")>
Private Shared Function TrackPopupMenu(ByVal hMenu As IntPtr, ByVal uFlags As Integer, _
    ByVal x As Integer, ByVal y As Integer, ByVal nReserved As Integer, _
    ByVal hWnd As IntPtr, ByVal prcRect As IntPtr) As Integer
End Function
<DllImport("user32.dll")>
Private Shared Function SendMessage(ByVal hWnd As IntPtr, ByVal msg As Integer, _
    ByVal wParam As IntPtr, ByVal lParam As IntPtr) As IntPtr
End Function

并以这种方式显示菜单：

Dim menu = GetSystemMenu(Me.Handle, False)
Dim command = TrackPopupMenu(menu, TPM_RETURNCMD + TPM_LEFTBUTTON + TPM_RIGHTBUTTON, _
                    MousePosition.X, MousePosition.Y, IntPtr.Zero, _
                    Me.Handle, IntPtr.Zero)
If (command > 0) Then
    SendMessage(Me.Handle, WM_SYSCOMMAND, command, IntPtr.Zero)
End If