event DropDown (Cancel as Variant)
Occurs when the drop-down portion of the control is shown.

TypeDescription
Cancel as Variant A Boolean expression that specifies whether to cancel showing the drop down portion of the control. 

Use the DropDown and DropUp events to notify your application that the drop-down portion of the control is shown or hidden. Use the DropDown event to cancel showing the drop down portion of the control based on your condition. The DropDown and DropUp events are fired only if the control's Style property is DropDown or DropDownList. Use the hWndDropDown property to get the handle of the drop down window. Use the DropDown method to show programmatically the drop down portion of the control. The AutoDropDown property retrieves or sets a value that indicates whether the control's list automatically drops down once the user starts type into it.

The following VB sample disable showing the drop down portion of the control if there is no items: 

Private Sub ComboBox1_DropDown(Cancel As Variant)
    Cancel = ComboBox1.Items.ItemCount = 0
End Sub

Syntax for DropDown event, /NET version, on: 

private void DropDown(object sender,ref object Cancel)
{
}


Private Sub DropDown(ByVal sender As System.Object,ByRef Cancel As Object) Handles DropDown
End Sub

Syntax for DropDown event, /COM version, on: 

private void DropDown(object sender, AxEXCOMBOBOXLib._IComboBoxEvents_DropDownEvent e)
{
}


void OnDropDown(VARIANT FAR* Cancel)
{
}


void __fastcall DropDown(TObject *Sender,Variant * Cancel)
{
}


procedure DropDown(ASender: TObject; var Cancel : OleVariant);
begin
end;


procedure DropDown(sender: System.Object; e: AxEXCOMBOBOXLib._IComboBoxEvents_DropDownEvent);
begin
end;


begin event DropDown(any Cancel)
end event DropDown


Private Sub DropDown(ByVal sender As System.Object, ByVal e As AxEXCOMBOBOXLib._IComboBoxEvents_DropDownEvent) Handles DropDown
End Sub


Private Sub DropDown(Cancel As Variant)
End Sub


Private Sub DropDown(Cancel As Variant)
End Sub


LPARAMETERS Cancel



PROCEDURE OnDropDown(oComboBox,Cancel)
RETURN

Syntax for DropDown event, /COM version (others), on: 

<SCRIPT EVENT="DropDown(Cancel)" LANGUAGE="JScript">
</SCRIPT>


<SCRIPT LANGUAGE="VBScript">
Function DropDown(Cancel)
End Function
</SCRIPT>


Procedure OnComDropDown Variant llCancel
	Forward Send OnComDropDown llCancel
End_Procedure


METHOD OCX_DropDown(Cancel) CLASS MainDialog
RETURN NIL


void onEvent_DropDown(COMVariant /*variant*/ _Cancel)
{
}


function DropDown as v (Cancel as A)
end function


function nativeObject_DropDown(Cancel)
return