รบกวนถามเรื่อง คอมโบบ๊อกหน่อยคับ อยากรู้วิธีใช้มันอ่ะคัฟ

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim _DR As DataRow
        Dim _DT As New DataTable

        _DT.Columns.Add("Data")
        _DT.Columns.Add("SQLString")

        _DR = _DT.NewRow
        _DR("Data") = "น้อยกว่า 1175"
        _DR("SQLString") = "Transformer_size < 1175"
        _DT.Rows.Add(_DR)

        _DR = _DT.NewRow
        _DR("Data") = "1175 ถึง 3529"
        _DR("SQLString") = "Transformer_size >= 1175 And Transformer_size <= 3529"
        _DT.Rows.Add(_DR)

        _DR = _DT.NewRow
        _DR("Data") = "มากกว่า 3529"
        _DR("SQLString") = "Transformer_size > 3529"
        _DT.Rows.Add(_DR)

        ComboBox1.DataSource = _DT
        ComboBox1.DisplayMember = "Data"
        ComboBox1.ValueMember = "SQLString"

        
    End Sub

    Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
        Try
            Me.Text = ComboBox1.SelectedValue
        Catch ex As Exception
            ComboBox1.Text = Nothing
        End Try

    End Sub