Setting the Height of a ComboBox Control

.NET Framework 1.1 does not provide a way to change the height of a combobox control. This can be achieved by sending CB_SETITEMHEIGHT with −1 as index to the combobox control:

Private Declare Auto Function SendMessage Lib "user32.dll" ( _
    ByVal hWnd As IntPtr, _
    ByVal wMsg As Int32, _
    ByVal wParam As IntPtr, _
    ByVal lParam As IntPtr _
) As IntPtr

Private Const CB_ERR As Int32 = -1
Private Const CB_SETITEMHEIGHT As Int32 = &H153

Private Function SetComboBoxEditHeight( _
    ByVal ComboBox As ComboBox, _
    ByVal Height As Integer _
) As Boolean
    Return _
        SendMessage( _
            ComboBox.Handle, _
            CB_SETITEMHEIGHT, _
            New IntPtr(-1), New IntPtr(Height) _
        ) <> New IntPtr(CB_ERR)
End Function


Debug.Assert(SetComboBoxEditHeight(Me.ComboBox1, 50))