I've tried deploying my asp.net app to a new server and I get this error:

Could not load file or assembly 'S开发者_StackOverflow中文版ystem.Web.Entity, Version=3.5.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' or one of its dependencies. The system cannot find the file specified.

Sure enough, System.Web.Entity isn't found in C:\Windows\Assembly. However, the server has MS .NET Framework 3.5 installed and also MS ASP.NET 2.0 AJAX Extensions 1.0.

Is this something I need to deploy with my app, or something I need to be installed on the server? It's not my own server so xcopy deployment within my app folder would be much better if that's possible.

(Sorry this is probably a real newbie question.)

thanks!

Do you really use/need the EntityDataSource on the deployment server ?

If not, just remove this line.

Could not load file or assembly 'System.Web.Entity, Version=3.5.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' or one of its dependencies. The system cannot find the file specified.

Some information about EntityDataSource.

EntityDataSource is a new DataSource control for ASP.Net (just like ObjectDataSource and SQLDataSource and more recent - LinqDataSource) which makes declaratively binding ASP.NET UI controls to Entity Data Models very easy.

more on
http://blogs.microsoft.co.il/blogs/bursteg/archive/2008/05/12/EntityDataSource-Entity-Data-Source.aspx

In my web.config this does not exist neither on 2008/2010 vs projects.

It turned out the dependency was on .NET framework 3.5 SP1

But also I was able to do without the reference, as @Aristos suggested.

I was getting the same error but for .Net 4.5 assemblies.

Could not load file or assembly 'System.Web.Entity, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' or one of its dependencies. The system cannot find the file specified.

Solution:

Through detailed debugging log in VS 2012 output i found the following location missing the dll. I had to copy from another machine to resolve.

C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Web.Entity\v4.0_4.0.0.0__b77a5c561934e089

Please don't copy from C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETFramework\v4.5 which is a reference assembly throws same error again.