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
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))
To hide a specific column in a lookupedit control of devexpress is:
lookUpEdit1.Properties.PopulateColumns();
lookUpEdit1.Properties.Columns[**index**].Visible = false;
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