Trying to understand PopUp Menus!

[Guido Meng]

Hi All!

I'm an amateur programmer and just recently came across a piece of code to build popup menus with the right-click of the mouse. It works!, I think I can adapt it and use it to enhance my own code however, since I don't fully understand how it works, I'd feel like the Apes in Planet of the apes when they pulled a car with horses not knowing any better . What I understand is this:

1) A bunch of functions (I think, pre-built for usage on almost any programming language) are used to build the menu, destroy it when no longer needed, etc.
2) There are other ways to build the PopUp menus, I think, but I'm not sure if they would be quiet as effective or at least as easy and flexible to use.
3) What really confuses me the most is the usage of things like: * <-----------------------

Private Type POINTAPI
    X As Long
    Y As Long
End Type
'
Private Declare Function CreatePopupMenu Lib "user32" () As Long
Private Declare Function TrackPopupMenuEx Lib "user32" _
        (ByVal hMenu As Long, ByVal wFlags As Long, ByVal X As Long, ByVal Y As Long, _
ByVal hWnd As Long, ByVal lptpm As Any) As Long
Private Declare Function AppendMenu Lib "user32" Alias "AppendMenuA" _
        (ByVal hMenu As Long, ByVal wFlags As Long, ByVal wIDNewItem As Long, _
        ByVal lpNewItem As Any) As Long
Private Declare Function DestroyMenu Lib "user32" (ByVal hMenu As Long) As Long
Private Declare Function GetCursorPos Lib "user32" (lpPoint As POINTAPI) As Long
Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" _
        (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
'
Const MF_CHECKED = &H8&         '   <------------------------------------     THIS IS SO WEIRD, WELL, AT LEAST FOR ME HEHEHE.
Const MF_APPEND = &H100&        '   <------------------------------------     THIS IS SO WEIRD, WELL, AT LEAST FOR ME HEHEHE.
Const TPM_LEFTALIGN = &H0&      '   <------------------------------------     THIS IS SO WEIRD, WELL, AT LEAST FOR ME HEHEHE.
Const MF_SEPARATOR = &H800&     '   <------------------------------------     THIS IS SO WEIRD, WELL, AT LEAST FOR ME HEHEHE.
Const MF_STRING = &H0&          '   <------------------------------------     THIS IS SO WEIRD, WELL, AT LEAST FOR ME HEHEHE.
Const TPM_RETURNCMD = &H100&    '   <------------------------------------     THIS IS SO WEIRD, WELL, AT LEAST FOR ME HEHEHE.
Const TPM_RIGHTBUTTON = &H2&    '   <------------------------------------     THIS IS SO WEIRD, WELL, AT LEAST FOR ME HEHEHE.
'
Dim hMenu As Long
Dim hWnd As Long
'
Private Sub UserForm_Initialize()
    hWnd = FindWindow(vbNullString, Me.Caption)
End Sub
'
Private Sub UserForm_MouseUp(ByVal Button As Integer, ByVal Shift As Integer, ByVal X As Single, ByVal Y As Single)
 Dim Pt As POINTAPI
    Dim ret As Long
    If Button = 2 Then
        hMenu = CreatePopupMenu()
        AppendMenu hMenu, MF_STRING, 1, "Menu - 1"
        AppendMenu hMenu, MF_STRING, 2, "Menu - 2"
        AppendMenu hMenu, MF_SEPARATOR, 3, ByVal 0&
        AppendMenu hMenu, MF_STRING, 4, "About"
        GetCursorPos Pt
        ret = TrackPopupMenuEx(hMenu, TPM_LEFTALIGN Or TPM_RETURNCMD Or _
                               TPM_RIGHTBUTTON, Pt.X, Pt.Y, hWnd, ByVal 0&)
        DestroyMenu hMenu
        
            Select Case ret
                Case 1
                Call MenuProc1
                Case 2
                Call MenuProc2
                Case 4
                Call MenuProc3
            End Select
    End If
End Sub
'
Private Sub MenuProc1()
    MsgBox "PopUp menu-1 is activated !"
End Sub
'
Private Sub MenuProc2()
    MsgBox "PopUp menu-2 is activated !"
End Sub
'
Private Sub MenuProc3()
    MsgBox "Prepared by Raider ®"
End Sub

MF_SEPARATOR = &H800& <---------- What is this? some sort of hexadecimal notation? what is it used for? is there any advantage for using this?

for any help or guidance Thanks a lot !



















Const MF_SEPARATOR = &H800&, then later a parameter in other words, why the need of constants instead of just