Rellenar un ComboBox con un DataReader

Imports System
Imports System.Data
Imports System.Data.SqlClient
Imports System.Windows.Forms
 
 ' ...
 Dim con As SqlConnection = Nothing
 Dim command As SqlCommand = Nothing
 Dim cs As String = "cadena de conexión SQL"
 Dim dr As SqlDataReader = Nothing
 
 Try
   con = New SqlConnection(cs)
   command = New SqlCommand("SELECT campo FROM Tabla",con)
 
   ' abrir la conexión
   con.Open()
   dr = command.ExecuteReader()
 
   ' vaciar ComboBox 
   ComboBox1.Items.Clear()
 
   If dr.HasRows Then
     While dr.Read
       ComboBox1.Items.Add(dr.GetValue(0))
     End While
   Else
     MessageBox.Show("No result for your Data", "Infos", 
MessageBoxButtons.OK, MessageBoxIcon.Information)
   End If
 Catch ex As Exception
   MessageBox.Show(ex.Message)
 Finally
   If Not (dr Is Nothing) Then dr.Close()
   If Not (con Is Nothing) Then con.Close()
 End Try
 
' ...