The BeforeExandGroup event notifies your application that a group is expanding or collapsing. Use the BeforeExapndGroup event to cancel the expanding/collapsing operation. The control fires the ExpandGroup event after group is expanded or collapsed. Use the Expanded property to expand programmatically the group. Use the DisplayExpandIcon property to show or hide the expand icon on the group's caption.

The following VB sample disables expanding or collapsing the first group:

Private Sub ExplorerBar1_BeforeExpandGroup(ByVal Group As EXPLORERBARLibCtl.IGroup, Cancel As Boolean)
    With Group
        If .Index = 0 Then
            Cancel = True
        End If
    End With
End Sub

The following C++ sample disables expanding or collapsing the first group:

void OnBeforeExpandGroupExplorerbar1(LPDISPATCH Group, BOOL FAR* Cancel) 
{
	CGroup group( Group ); group.m_bAutoRelease = FALSE;
	if ( group.GetIndex() == 0 )
		*Cancel = TRUE;
}

The following VB.NET sample disables expanding or collapsing the first group:

Private Sub AxExplorerBar1_BeforeExpandGroup(ByVal sender As Object, ByVal e As AxEXPLORERBARLib._IExplorerBarEvents_BeforeExpandGroupEvent) Handles AxExplorerBar1.BeforeExpandGroup
    With e.group
        If (.Index = 0) Then
            e.cancel = True
        End If
    End With
End Sub

The following C# sample disables expanding or collapsing the first group:

private void axExplorerBar1_BeforeExpandGroup(object sender, AxEXPLORERBARLib._IExplorerBarEvents_BeforeExpandGroupEvent e)
{
	if (e.group.Index == 0)
		e.cancel = true;
}

The following VFP sample disables expanding or collapsing the first group:

*** ActiveX Control Event ***
LPARAMETERS group, cancel

With Group
    If .Index = 0 Then
        Cancel = .t.
    EndIf
EndWith