web asp.net คือไม่รู้ว่าผิดตรงไหนอ่าคับรบกวนที Both DataSource and DataSourceID are defined on ‘GridView1′. Remove one definition.

 Protected Sub Btn_Add_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Btn_Add.Click
        Dim connStr As String = ConfigurationManager.ConnectionStrings("testConnectionString").ConnectionString.ToString()
        Dim conn As New SqlConnection(connStr)
        Dim cmd As New SqlCommand()
        cmd.CommandText = "INSERT INTO Table_Roomdata(D_ID,D_NR,D_PT,D_Phon,D_PE,D_Date)" & _
            " VALUES(@D_ID,@D_NR,@D_PT,@D_Phon,@D_PE,@P_Date) "

        cmd.Parameters.Add("@D_ID", SqlDbType.VarChar).Value = txt_D_ID.Text
        cmd.Parameters.Add("@D_NR", SqlDbType.VarChar).Value = txt_D_NR.Text
        cmd.Parameters.Add("@D_PT", SqlDbType.VarChar).Value = txt_D_PT.Text
        cmd.Parameters.Add("@D_Phon", SqlDbType.VarChar).Value = txt_D_Phon.Text
        cmd.Parameters.Add("@D_PE", SqlDbType.VarChar).Value = txt_D_PE.Text
        cmd.Parameters.Add("@D_Date", SqlDbType.DateTime).Value = DateTime.Now

        cmd.Connection = conn
        conn.Open()
        cmd.ExecuteNonQuery()
        conn.Close()

        GetData()
Protected Sub GetData()
        Dim CondStr As String = ""
        If txt_Search.Text <> "" Then
            CondStr = " and (D_ID like '" & txt_Search.Text & "%' OR D_NAME like '" & txt_Search.Text & "%')"
        End If

        Dim connStr As String = ConfigurationManager.ConnectionStrings("testConnectionString").ConnectionString.ToString()
        Dim conn As New SqlConnection(connStr)
        conn.Open()


        Dim da As New SqlDataAdapter("select * from Table_Roomdata where 1=1 " & CondStr, conn)
        Dim ds As New DataSet()
        da.Fill(ds)
        conn.Close()

        GridView1.DataSource = ds
        GridView1.DataBind()

        txt_Count.Text = GridView1.Rows.Count.ToString()

    End Sub

DataList1.DataSourceID = null;
DataList1.DataSource = objPds;
DataList1.DataBind();