property Editor.ExpandItem(Value as Variant) as Boolean
Expandes or collapses an item in the editor's list.

TypeDescription
Value as Variant A long expression that indicates the value of the item being expanded, a string expression that indicates the caption of the item being expanded.
Boolean A boolean expression that indicates whether the item is expanded or collapsed.
By default, the items are collapsed. Use the ExpandItem to expand a specified item. Use the ExpandAll method to expand all items in the editor. Use the InsertItem method to insert a child item to your drop down editor. The ExpandItem property has effect only if the EditType property is DropDownListType.

The following VB sample expands all items in the DropDownListType editor:

With Record1
    .BeginUpdate
    With .Add("DropDownList", EXRECORDLibCtl.DropDownListType)
        .DropDownAutoWidth = False
        .AddItem 0, "Root 1"
        .InsertItem 1, "Child 1", , 0
        .InsertItem 2, "Child 2", , 0
        .InsertItem 3, "SubChild 2.1", , 2
        .InsertItem 4, "SubChild 2.2", , 2
        .AddItem 5, "Root 2"
        .InsertItem 6, "Child 1", , 5
        .InsertItem 7, "Child 2", , 5
        .InsertItem 8, "SubChild 2.1", , 6
        .InsertItem 9, "SubChild 2.2", , 6
        .ExpandAll
        .Value = 6
    End With
    .EndUpdate
End With

The following VC sample expands all items in a DropDownListType editor:

COleVariant vtMissing; vtMissing.vt = VT_ERROR;
CEditor editor = m_record.Add(COleVariant("DropDownList"), /*DropDownListType*/ 3, vtMissing );
editor.SetDropDownAutoWidth( FALSE );
editor.AddItem( 0, "Root 1", vtMissing );
editor.InsertItem( 1, "Child 1", vtMissing, COleVariant( long(0) ) );
editor.InsertItem( 2, "Child 2", vtMissing, COleVariant( long(0) ) );
editor.InsertItem( 3, "SubChild 2.1", vtMissing, COleVariant( long(2) ) );
editor.InsertItem( 4, "SubChild 2.2", vtMissing, COleVariant( long(2) ) );
editor.AddItem( 5, "Root 2", vtMissing );
editor.InsertItem( 6, "Child 1", vtMissing, COleVariant( long(0) ) );
editor.InsertItem( 7, "Child 2", vtMissing, COleVariant( long(0) ) );
editor.InsertItem( 8, "SubChild 1.1", vtMissing, COleVariant( long(6) ) );
editor.InsertItem( 9, "SubChild 1.2", vtMissing, COleVariant( long(6) ) );
editor.SetValue( COleVariant( (long)6 ) );
editor.ExpandAll();