ถ้าเราดึง ข้อมูลจากตารางในฐานข้อมูลมาใส่ combobox แล้วแสดงค่าใน label

Dim strConn As String
        strConn = DBConnString.strConn

        Conn = New OleDbConnection()
        With Conn
            If .State = ConnectionState.Open Then .Close()
            .ConnectionString = strConn
            .Open()
        End With

        sb1 = New StringBuilder()
        sb1.Append("SELECT * FROM tb_respon;")
        Dim sqlrespon As String
        sqlrespon = sb1.ToString()
        Com = New OleDbCommand()
        With Com
            .CommandText = sqlrespon
            .CommandType = CommandType.Text
            .Connection = Conn
            dr1 = .ExecuteReader()
        End With
        If dr1.HasRows Then
            dtrespon = New DataTable()
            dtrespon.Load(dr1)
            With cb_rsp
                .BeginUpdate()
                .DisplayMember = "name_rpn"
                .ValueMember = "id_rpn"
                .DataSource = dtrespon
                .EndUpdate()
            End With
        End If

Dim strConn As String
        strConn = DBConnString.strConn

        Conn = New OleDbConnection()
        With Conn
            If .State = ConnectionState.Open Then .Close()
            .ConnectionString = strConn
            .Open()
        End With

        'Dim daole As OleDb.OleDbDataAdapter สร้าง data adapter ซ่ะ
        'Dim dt As DataTable = New DataTable สร้าง data table ซ่ะ
        sb1 = New StringBuilder()
        sb1.Append("SELECT * FROM tb_respon;")
        Dim sqlrespon As String
        sqlrespon = sb1.ToString()
        Com = New OleDbCommand()
        With Com
            .CommandText = sqlrespon
            .CommandType = CommandType.Text
            .Connection = Conn
            dr1 = .ExecuteReader()
            'daole = New OleDb.SqlDataAdapter(Com)
            'daole.Fill(dt) จับมันยัดลง databable

        End With
        If dr1.HasRows Then
            dtrespon = New DataTable()
            dtrespon.Load(dr1)
            With cb_rsp
                .BeginUpdate()
                .DisplayMember = "name_rpn"
                .ValueMember = "id_rpn"
                .DataSource = dtrespon
                .EndUpdate()
            End With
        End If

Dim strConn As String
        strConn = DBConnString.strConn

        Conn = New OleDbConnection()
        With Conn
            If .State = ConnectionState.Open Then .Close()
            .ConnectionString = strConn
            .Open()
        End With

        sb1 = New StringBuilder()
        sb1.Append("SELECT * FROM tb_respon;")
        Dim sqlrespon As String
        sqlrespon = sb1.ToString()
        Com = New OleDbCommand()
        With Com
            .CommandText = sqlrespon
            .CommandType = CommandType.Text
            .Connection = Conn
            dr1 = .ExecuteReader()
        End With
        If dr1.HasRows Then
            dtrespon = New DataTable()
            dtrespon.Load(dr1)
            With cb_rsp
                .BeginUpdate()
                .DisplayMember = "name_rpn"
                .ValueMember = "id_rpn"
                .DataSource = dtrespon
                .EndUpdate()
            End With
        End If

Sub DropDownList_SelectedIndexChanged(sender as Object, e As System.EventArgs) Handles DropDownList.SelectedIndexChanged
Dim strConn As String
        strConn = DBConnString.strConn

        Conn = New OleDbConnection()
        With Conn
            If .State = ConnectionState.Open Then .Close()
            .ConnectionString = strConn
            .Open()
        End With

        sb1 = New StringBuilder()
        sb1.Append("SELECT * FROM tb_respon WHERE Column_Name ='" & cb_rsp.Selectedvalue &"'")
        Dim sqlrespon As String
        sqlrespon = sb1.ToString()
        Com = New OleDbCommand()
        With Com
            .CommandText = sqlrespon
            .CommandType = CommandType.Text
            .Connection = Conn
            dr1 = .ExecuteReader()
        End With
        If dr1.HasRows Then

            'ให้แสดงรายละเอียด ก็ว่ากันไป

        End If

End Sub