VB - Show/Hide ComboBox Dropdown List

[John McKernan]

Summary:
Procedure allows you to programatically show or hide a combobox's dropdown list.

Arguments:
WhichCombo - a reference to the combobox
DropItDown - Boolean: True to Show list, False to Hide list

'declare api procedures
    Public Declare Function SendMessage Lib "user32" Alias "SendMessageA" _
        (ByVal hwnd As Long, _
        ByVal wMsg As Long, _
        ByVal wParam As Long, _
        lParam As Any) As Long  
 
'declare constants
    Public Const CB_SHOWDROPDOWN = &H14F
 
 
Public Sub DropList(WhichCombo As Control, DropItDown As Boolean)
    On Error Resume Next
 
    Dim vTmpLng as Long
    vTmpLng = SendMessage(WhichCombo.hWnd, CB_SHOWDROPDOWN, _
                  ByVal Abs(CLng(DropItDown)), ByVal CLng(0))
End Sub

Usage Example:

DropList Form1.Combo1, True

Notes:
As written, this code is intended to be placed in a module, and then called as needed. In order to place this code in a form, you will have to change the API and Constant declarations to 'Private'