gridview-Get error when trying to bind, something about idatasource

I am trying to work with gridview but it gives me the following error (on binding)
:

[B]Exception Details: [FONT=Arial]System.Web.HttpException: The DataSourceID of 'GridView1' must be the ID of a control of type IDataSource.  A control with ID 'grade' could not be found.[/FONT]
[/B]

Code (markup):

This is my client code:

<%@ Page Title="" Language="C#" MasterPageFile="~/master.Master" AutoEventWireup="true" CodeBehind="GradesDisplay.aspx.cs" Inherits="Project2012.GradesDisplay" %><asp:Content ID="Content1" ContentPlaceHolderID="head" runat="server"></asp:Content><asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="server">       <asp:GridView ID="GridView1" runat="server"         DataSourceID="JTutor2.grade" Height="128px" Width="305px" AllowPaging="True"         AllowSorting="True" CellPadding="4" ForeColor="#333333" GridLines="None">        <AlternatingRowStyle BackColor="White" />               <EditRowStyle BackColor="#2461BF" />        <FooterStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />        <HeaderStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />        <PagerStyle BackColor="#2461BF" ForeColor="White" HorizontalAlign="Center" />        <RowStyle BackColor="#EFF3FB" />        <SelectedRowStyle BackColor="#D1DDF1" Font-Bold="True" ForeColor="#333333" />        <SortedAscendingCellStyle BackColor="#F5F7FB" />        <SortedAscendingHeaderStyle BackColor="#6D95E1" />        <SortedDescendingCellStyle BackColor="#E9EBEF" />        <SortedDescendingHeaderStyle BackColor="#4870BE" />    </asp:GridView>       <asp:SqlDataSource ID="SqlDataSource1" runat="server"         ConnectionString="<%$ ConnectionStrings:JTutor2 %>"                  SelectCommand="SELECT grade.User_ID, grade.Grade_date, grade.Grade_grade, Lesson.lesson_name FROM grade INNER JOIN Lesson ON grade.Lesson_ID = Lesson.ID WHERE (grade.User_ID = @user_id)">        <SelectParameters>            <asp:Parameter Name="user_id" />        </SelectParameters>    </asp:SqlDataSource>  </asp:Content>

HTML:

And this is my server code:

User usr=(User)Session["User"];                      
           SqlDataSource1.SelectParameters["User_id"].DefaultValue = usr.User_ID;

Code (markup):

 

Check the DataSourceID in your client code. there a is big error