fill combobox from another combobox

Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
        Dim adapter As New SqlDataAdapter()
        Dim ds As New DataSet()
        Dim con As New SqlConnection("Data Source=.;Initial Catalog=system saling;Integrated Security=True")


        Try
            If IsNumeric(ComboBox1.SelectedValue) Then

                Dim com As New SqlCommand("select id_col,collection_name from colec_items where (card_no = '" & ComboBox1.SelectedValue & "')", con)
                con.Open()
                adapter.SelectCommand = com
                adapter.Fill(ds)
                adapter.Dispose()
                com.Dispose()
                con.Close()


                ComboBox2.DataSource = ds.Tables(0)
                ComboBox2.ValueMember = "id_col"
                ComboBox2.DisplayMember = "collection_name"
            End If
        Catch ex As Exception
            'MessageBox.Show("errogggggggggggggvgr")
        End Try


    End Sub

Private Sub ComboBox2_SelectedValueChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ComboBox2.SelectedValueChanged
       Dim adapter As New SqlDataAdapter()
       Dim ds As New DataSet()
       Dim con As New SqlConnection("Data Source=.;Initial Catalog=system saling;Integrated Security=True")



       Try
           If IsNumeric(ComboBox2.SelectedValue) Then

               Dim com As New SqlCommand("select item_no,item_name from item_info where (collec_no = '" + ComboBox2.SelectedValue + "')", con)
               con.Open()
               adapter.SelectCommand = com
               adapter.Fill(ds)
               adapter.Dispose()
               com.Dispose()
               con.Close()


               ComboBox3.DataSource = ds.Tables(0)
               ComboBox3.ValueMember = "item_no"
               ComboBox3.DisplayMember = "item_name"

           End If
       Catch ex As Exception

       End Try

   End Sub