隐藏LookUpEdit中的列（DevExpress）

Question

I am trying hide all columns of a LookUpEdit control (DevExpress 3rd party) except the DisplayMember (Its functionality should seems as stander ComboBox)

The Properties.DataSource is a DataTable, so when I want to access to each column for hiding it, programs launches Null ref exception.

What am I doing wrong?

The code:

If TypeOf Me.Properties.DataSource Is DataTable Then
     Me.Properties.PopulateColumns()
     Dim dt As DataTable = CType(Me.Properties.DataSource, DataTable)

     For Each column As DataColumn In dt.Columns
         If Me.Properties.Columns(column.ColumnName) IsNot Nothing AndAlso column.ColumnName IsNot Me.DisplayMember Then
                Me.Properties.Columns(column.ColumnName).Visible = False
         End If
     Next

End If

Answer 1

Instead of hiding columns you can add only one column that you need:

lookUpEdit1.Properties.Columns.Add(New LookUpColumnInfo(lookUpEdit1.Properties.DisplayMember))

Here is example:

Dim dataTable As New DataTable()

dataTable.Columns.Add("ID", Type.GetType("System.Int32"))
dataTable.Columns.Add("Name", Type.GetType("System.String"))
dataTable.Columns.Add("Description", Type.GetType("System.String"))

dataTable.Rows.Add(0, "Name0", "Description0")
dataTable.Rows.Add(1, "Name1", "Description1")
dataTable.Rows.Add(2, "Name2", "Description2")

lookUpEdit1.Properties.DataSource = dataTable
lookUpEdit1.Properties.DisplayMember = "Name"
lookUpEdit1.Properties.ValueMember = "ID"

lookUpEdit1.Properties.Columns.Add(New LookUpColumnInfo(lookUpEdit1.Properties.DisplayMember))

Answer 2

To hide a specific column in a lookupedit control of devexpress is:

lookUpEdit1.Properties.PopulateColumns();
lookUpEdit1.Properties.Columns[**index**].Visible = false;