The HasButtons property has effect only if the data is displayed as a tree. Use the InsertItem method to insert child items. The control displays a +/- button to parent items, if the HasButtons property is not zero, the ItemChild property is not empty, or the ItemHasChildren property is True. The user can click the +/- button to expand or collapse the child items. Use the ExpandItem property of Items object to programmatically expand/collapse an item. The HasButtonsCustom property specifies the index of icons being used for +/- signs on parent items, when HasButtons property is exCustom.

The following VB sample changes the +/- button appearance:

With ComboBox1
    .HasButtons = ExpandButtonEnum.exWPlus
End With

The following C++ sample changes the +/- button appearance:

m_combobox.SetHasButtons( 3 /*exWPlus*/ );

The following VB.NET sample changes the +/- button appearance:

With AxComboBox1
    .HasButtons = EXCOMBOBOXLib.ExpandButtonEnum.exWPlus
End With

The following C# sample changes the +/- button appearance:

axComboBox1.HasButtons = EXCOMBOBOXLib.ExpandButtonEnum.exWPlus;

The following VFP sample changes the +/- button appearance:

with thisform.ComboBox1
	.HasButtons = 3 && exWPlus
endwith