Question

my test:

Public Class Form1

   Public Const WM_SYSCOMMAND As Int32 = &H112
   Public Const MF_BYPOSITION As Int32 = &H400
   Public Const MYMENU1 As Int32 = 1000
   Public Const MYMENU2 As Int32 = 1001

   Dim hSysMenu As Long


   Private Declare Function GetSystemMenu Lib "user32" (ByVal hwnd As Long, ByVal bRevert As Long) As Long
   Public Declare Function InsertMenu Lib "user32" Alias "InsertMenuA" _
       (ByVal hMenu As IntPtr, ByVal nPosition As Long, ByVal wFlags As Long, ByVal wIDNewItem As Long, ByVal lpNewItem As String) As Boolean

   Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)
      MyBase.WndProc(m)
      If (m.Msg = WM_SYSCOMMAND) Then
         Select Case m.WParam.ToInt32
            Case MYMENU1
               MsgBox("1")
            Case MYMENU2
               MsgBox("2")
         End Select
      End If
   End Sub

   Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
      hSysMenu = GetSystemMenu(Me.Handle, False)
      InsertMenu(hSysMenu, 5, MF_BYPOSITION, MYMENU1, "My Menu 1")
      InsertMenu(hSysMenu, 6, MF_BYPOSITION, MYMENU2, "My Menu 2")

   End Sub
End Class

and i get an error:

PInvokeStackImbalance was detected
Message: A call to PInvoke function ‘WindowsApplication1!WindowsApplication1.Form1::GetSystemMenu’ has unbalanced the stack. This is likely because the managed PInvoke signature does not match the unmanaged target signature. Check that the calling convention and parameters of the PInvoke signature match the target unmanaged signature.

Answer 1

Replace Long with Integer in your declarations.