Entity DataSource not working with Entity Framework 6 Upgrade

问题

I recently upgraded our Webforms application from EF 4.4 to EF6 and I got so many compile time build errors with the Entity Datasource controls. Generally I am getting these error in all occurrences when trying to access the context object :

e.Context

I have followed the same walkthrough as given in : http://entityframework.codeplex.com/wikipage?title=Updating%20Applications%20to%20use%20EF6

The error information which is showing up is:

1) Module System.Data.Entity. version="4.0.0.0" should be referenced

2) Cannot case expression of type System.Data.Objects.ObjectContext to type ObjectContext (After explicitly type casting to System.Data.Entity.Core.Objects.ObjectContext)

Can anybody help to fix this?

回答1:

I just went through this exercise when upgrading to EF 6 from EF 5 and I had the same errors.

Here is what I had to do.

Install-Package Microsoft.AspNet.EntityDataSource

It would register a new EntityDataSource Control in the web.config under pages:

<pages>
  <controls>
    <add tagPrefix="ef" assembly="Microsoft.AspNet.EntityDataSource" namespace="Microsoft.AspNet.EntityDataSource" />
  </controls>
</pages>

Next step is to replace existing <asp:EntityDataSource /> controls to <ef:EntityDataSource /> in your aspx pages.

Final step is to go in your code behind and update references for EntityDataSourceContextCreatingEventArgs or any other type of EFContext tags.

From

protected void OnContextCreating(object sender, EntityDataSourceContextCreatingEventArgs e){... } 

To

protected void OnContextCreating(object sender, Microsoft.AspNet.EntityDataSource.EntityDataSourceContextCreatingEventArgs e){... } 

It all worked and I didn't have to reference System.Data.Entity in the assembly.

回答2:

The Entity DataSource control for EF6 is available in preview since 2014-01-30 (details in this Microsoft announcement). It is available as a nuget package : http://www.nuget.org/packages/Microsoft.AspNet.EntityDataSource/

If you try to download it from the nuget package manager, be sure to select the "include prerelease" item in the top combo Box.

回答3:

As per the suggestions given by the IDE, we can go to the NuGet Package Console and run the following command to install the new Entity Framework data source:

Install-Package Microsoft.AspNet.EntityDataSource

Also, add the following package (as referred in this article):

Install-Package Microsoft.AspNet.DynamicData.EFProvider

来源：https://stackoverflow.com/questions/19792144/entity-datasource-not-working-with-entity-framework-6-upgrade