maximize form using sendmessage api?

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im trying to maximize my form using the sendmessage api, i know i can do it by just chaning the windows state, but im looking for the way to do it using the sendmessage api

Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
 
Private Const WM_SIZE = &H5
 
Private Sub Command1_Click()
SendMessage Me.hwnd, WM_SIZE, 2, 0
End Sub

for some reason this wont work, using the WM_SIZE has the wParam 2 is = to maximizing