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data binding a aspx web forms dropdownlist to entity framework 6 database first model

Hi experts,

I saw this example on binding a web forms aspx dropdownlist to a Entity Framework 4 Database First model.

ADO.NET Entity Framework 4.0 : DataBinding with ASP.NET
http://blogs.msdn.com/b/wriju/archive/2010/06/03/ado-net-entity-framework-4-0-databinding-with-asp-net.aspx?Redirected=true

At the bottom of that page you can download their example.

So i downloaded their example and changed the web config file to point to my sql server database and ran it and their example worked fine.

One thing I noticed though about that example though is that it is using Entity Framework 4.

So I'm re-creating this example from scratch.
I want to re-create that example using Visual Studio 2013, C#, .Net Framework 4.5 and Entity Framework 6.0.

So this is what my project looks like.
All the code and naming conventions are the same as in their example.

This is my code for my page

WebForm1.aspx

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="WebApplication1.WebForm1" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:DropDownList ID="DropDownList1" runat="server" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged">
        </asp:DropDownList>
        <asp:GridView ID="GridView1" runat="server">
        </asp:GridView>    
    </div>
    </form>
</body>
</html>

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WebForm1.aspx.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace WebApplication1
{
    public partial class WebForm1 : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!Page.IsPostBack)
            {
                using (var ctx = new NorthwindEntities())
                {
                    DropDownList1.DataSource = ctx.Categories;

                    DropDownList1.DataTextField = "CategoryName";
                    DropDownList1.DataValueField = "CategoryID";

                    DropDownList1.DataBind();

                    int cid = (int.Parse(DropDownList1.SelectedValue));

                    GridView1.DataSource = (from p in ctx.Products
                                            where p.CategoryID == cid
                                            select p).ToList();
                    GridView1.DataBind();


                }
            }
        }

        protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
        {
            using (var ctx1 = new NorthwindEntities())
            {
                int cid = (int.Parse(DropDownList1.SelectedValue));

                GridView1.DataSource = (from p in ctx1.Products
                                        where p.CategoryID == cid
                                        select p).ToList();
                GridView1.DataBind();
            }
        }
    }
}

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My Web.config looks like this:

<?xml version="1.0" encoding="utf-8"?>
<!--
  For more information on how to configure your ASP.NET application, please visit
  http://go.microsoft.com/fwlink/?LinkId=169433
  -->
<configuration>
  <configSections>
    <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
    <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
  </configSections>
  <system.web>
    <compilation debug="true" targetFramework="4.5" />
    <httpRuntime targetFramework="4.5" />
  </system.web>
  <connectionStrings>
    <add name="NorthwindEntities" connectionString="metadata=res://*/NW.csdl|res://*/NW.ssdl|res://*/NW.msl;provider=System.Data.SqlClient;provider connection string=&quot;data source=MyServerName;initial catalog=Northwind;integrated security=True;MultipleActiveResultSets=True;App=EntityFramework&quot;" providerName="System.Data.EntityClient" />
  </connectionStrings>
  <entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework" />
    <providers>
      <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
    </providers>
  </entityFramework>
</configuration>

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But when I run my page I get this error:

Anyone know why I am getting this error? Anyone how I fix this error?

ASKER CERTIFIED SOLUTION

Randy Downs

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