CODEWITHSUNDEEP
c#asp.net.netentity-frameworklinq
Dimitar Nikovski
Dimitar Nikovski

Reputation: 973

How to access the Entity Framework data model from code behind in a web form?

I have generated an ADO.NET data model from my database in Visual Studio 2015, the generated class in myEntities.Context.cs is named myEntities and inherits from DbContext.

I want to extract objects data via LINQ from the model in code behind in MyPage.cs.

From my book and tutorials, I can see that to make this, you make an instance of the model class, in my case myEntities and run the LINQ query over it.

However, when I try to instance this class it is not found. The class is public in the namespace MyAppName.App_Code and MyPage.cs is in the namespace MyAppName.

I can't seem to include the MyAppName.App_Code namespace in my code behind for MyPage.cs, Visual Studio tells me that it's redundant and the code behind still doesn't see or accept the class myEntities.

Edit: More clear: In MyEntities.Context.cs in App_Code folder

namespace MyApp.App_Code
{
using System;
using System.Data.Entity;
using System.Data.Entity.Infrastructure;

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

Code behind of MyPage.cs

namespace MyApp
{
 public partial class _default : System.Web.UI.Page
 {
    public IQueryable ListView_GetData()
    {
        //can't use the MyEntities class here, tried to add the
        //MyApp.App_code namespace above, still did't work
        var data = MyEntities();

        //my LINQ operations

        return null;
    }
}}

Upvotes: 0

Views: 1450

Answers (1)

timothyclifford
timothyclifford

Reputation: 6969

From Microsoft documentation:

Code in the App_Code folder is referenced automatically in your application.

Putting your DbContext class in App_Code means it will be automatically available anywhere in your application without an explicit reference. So you would be able to write:

var exampleTableEntities = MyEntities.ExampleTableEntities;

If you want an explicit reference, I would suggest moving your DbContext outside the App_Code folder into a folder named Data, Domain or something similar. Then reference from your code file.

Upvotes: 1

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