Chapter 14: A Simple LINQ to Entities Example

phztfte1 · December 16th, 2015, 01:34 AM

Performed steps 8, 9, and 10 of the subject Try it Out. At step 10 when I view in the browser, I get the error message that the type or namespace name 'PlanetWroxEntities' could not be found (are you missing a using directive or an assembly reference?). The problem is from Line 12 of All.aspx.cs

Here is the code from All.aspx.cs:

Code:

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

public partial class Reviews_All : BasePage
{
    protected void Page_Load(object sender, EventArgs e)
    {
      using (PlanetWroxEntities myEntities = new PlanetWroxEntities())
    {
        var authorizedReviews = from review in myEntities.Reviews
                                where review.Authorized == true
                                orderby review.CreateDateTime descending
                                select review;
        GridView1.DataSource = authorizedReviews.ToList();
        GridView1.DataBind();
      }
    }
}

Here is the code from All.aspx:

<%@ Page Title="" Language="C#" MasterPageFile="~/MasterPages/Frontend.master" AutoEventWireup="true"
CodeFile="All.aspx.cs" Inherits="Reviews_All" %>

<asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="cpMainContent" Runat="Server">
<asp:GridView ID="GridView1" runat="server">
</asp:GridView>
</asp:Content>

Please help me fix the problem.

phztfte1 · December 16th, 2015, 09:31 AM

I am troubleshooting the problem and think I might have found a possible cause. Here is my web.config file:

Code:

<connectionStrings>
    <add name="PlanetWroxConnectionString1" connectionString="Data Source=(LocalDB)\v11.0;AttachDbFilename=|DataDirectory|\PlanetWrox.mdf;Integrated Security=True" providerName="System.Data.SqlClient" />
    <add name="PlanetWroxEntities" connectionString="metadata=res://*/App_Code.PlanetWrox.csdl|res://*/App_Code.PlanetWrox.ssdl|res://*/App_Code.PlanetWrox.msl;provider=System.Data.SqlClient;provider connection string=&quot;data source=(LocalDB)\v11.0;attachdbfilename=|DataDirectory|\PlanetWrox.mdf;integrated security=True;MultipleActiveResultSets=True;App=EntityFramework&quot;" providerName="System.Data.EntityClient" />
    <add name="PlanetWroxEntities1" connectionString="metadata=res://*/App_Code.PlanetWrox.csdl|res://*/App_Code.PlanetWrox.ssdl|res://*/App_Code.PlanetWrox.msl;provider=System.Data.SqlClient;provider connection string=&quot;data source=(LocalDB)\v11.0;attachdbfilename=|DataDirectory|\PlanetWrox.mdf;integrated security=True;multipleactiveresultsets=True;application name=EntityFramework&quot;" providerName="System.Data.EntityClient" />
    <add name="PlanetWroxEntities2" connectionString="metadata=res://*/App_Code.PlanetWrox.csdl|res://*/App_Code.PlanetWrox.ssdl|res://*/App_Code.PlanetWrox.msl;provider=System.Data.SqlClient;provider connection string=&quot;data source=(LocalDB)\v11.0;attachdbfilename=|DataDirectory|\PlanetWrox.mdf;integrated security=True;multipleactiveresultsets=True;application name=EntityFramework&quot;" providerName="System.Data.EntityClient" />
  </connectionStrings>

There are three PlantWroxEntities as I made several tries to get it right.

Here is the PlantWrox.Context.cs file:

//------------------------------------------------------------------------------
// <auto-generated>
// This code was generated from a template.
//
// Manual changes to this file may cause unexpected behavior in your application.
// Manual changes to this file will be overwritten if the code is regenerated.
// </auto-generated>
//------------------------------------------------------------------------------

using System;
using System.Data.Entity;
using System.Data.Entity.Infrastructure;

public partial class PlanetWroxEntities2 : DbContext
{
public PlanetWroxEntities2()
: base("name=PlanetWroxEntities2")
{
}

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
throw new UnintentionalCodeFirstException();
}

public virtual DbSet<Genres> Genres1 { get; set; }
public virtual DbSet<Reviews> Reviews1 { get; set; }
}

I think that the bold statement should refer to "PlanetWroxEntities" instead of "PlanetWroxEntities2".

Imar · December 16th, 2015, 10:20 AM

>> I think that the bold statement should refer to "PlanetWroxEntities" instead of "PlanetWroxEntities2".

Yes, either that, or update your code to use PlanetWroxEntities instead.

When you delete the model to start over, VS doesn't delete the connection string. Then when you add it, it finds PlanetWroxEntities in the web.config and adds a sequential number to make it unique. If you really want to start over, delete your edms, then delete your connection strings and then add the model again.

Cheers,

Imar

phztfte1 · December 17th, 2015, 12:26 AM

Thank you, Imar.

I chose to start all over again, and it worked.

Thank you once more.