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'Controls - How to add CheckBox to ComboBox

Option Explicit
 
'Add a Combo Box and a Check Box to your form and set CheckBox width property and height property to 130.

Declare Function FindWindowEx Lib "user32" Alias "FindWindowExA" (ByVal hwndParent As Long, _
    ByVal hwndChildAfter As Long, ByVal lpszClass As String, ByVal lpszWindow As String) As Long
Declare Function SendMessageLong Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, _
    ByVal wMsg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
Public Const EC_LEFTMARGIN = &H1
Public Const EC_RIGHTMARGIN = &H2
Public Const EC_USEFONTINFO = &HFFFF&
Public Const EM_SETMARGINS = &HD3&
Public Const EM_GETMARGINS = &HD4&
 
Private Sub AddCheckToCombo(ByRef chkThis As CheckBox, ByRef cboThis As ComboBox)
    Dim lhWnd As Long, lMargin As Long
    lhWnd = FindWindowEx(cboThis.hwnd, 0, "EDIT", vbNullString)
    If (lhWnd <> 0) Then
        lMargin = chkThis.Width \ Screen.TwipsPerPixelX + 2
        SendMessageLong lhWnd, EM_SETMARGINS, EC_LEFTMARGIN, lMargin
        chkThis.BackColor = cboThis.BackColor
        chkThis.Move cboThis.Left + 3 * Screen.TwipsPerPixelX, cboThis.Top + 2 * Screen.TwipsPerPixelY, _
            chkThis.Width, cboThis.Height - 4 * Screen.TwipsPerPixelY
        chkThis.ZOrder
    End If
End Sub
 
'How can I call this routine:
Private Sub Form_Load()
    AddCheckToCombo Check1, Combo1
End Sub