SQL = ... ORDER BY Name
mDA.SelectCommand = New SqlCommand(SQL, Cnn)
mDA.Fill(mDS, "CustomersByName")
 
SQL = ... ORDER BY Number
mDA.SelectCommand = New SqlCommand(SQL, Cnn)
mDA.Fill(mDS, "CustomersByNumber")
 
Dim data_relation As New DataRelation("Text", _
mDS.Tables("CustomersByName").Columns("K_ID"), _
mDS.Tables("CustomersByNumber").Columns("K_ID"))
mDS.Relations.Add(data_relation)
 
With cboCustomer
.DataSource = mDS.Tables("CustomersByName")
.DisplayMember = "Name"
.ValueMember = "K_ID"
.SelectedIndex = -1
End With
 
With cboMandantID
.DataSource = mDS.Tables("CustomersByNumber")
.DisplayMember = "Number"
.ValueMember = "K_ID"
.SelectedIndex = -1
End With