C# Devexpress How to code the CheckBox column header to select or deselect all

How to use C# code to program Devexpress gridView checkbox column header to show as check box, once it check or uncheck, it will select or deselect all the check box of the data row.

I already know how to program the check box below, i just could not find any clue to do the above. Need advise from all the master as i could.

Thank you, Brian

RepositoryItemCheckEdit repositoryCheckEdit1 = gridControl1.RepositoryItems.Add("CheckEdit") as RepositoryItemCheckEdit;
repositoryCheckEdit1.ValueChecked = "True";
repositoryCheckEdit1.ValueUnchecked = "False";
gridView1.Columns["Item"].ColumnEdit = repositoryCheckEdit1;