Visual Studio 2013 error creating EDMX file

Question

In Visual Studio 2013 (Update 2 and later Update 4) using Entity Framework 6.1.2, I am having problems creating an EDMX file.

When creating a file, I add a new element, select the "ADO.NET Entity Data Model" and regardless of whether I create an "empty EF Designer" or "EF Designer from the database" (and no matter which database I could would choose if you build a database). I get a very general error message:

"Operation is not valid due to the current state of the object"

and it returns me to the wizard for adding new elements. * .Edmx is created, but if I try to open the generated * .edmx file, I get another general message:

"Operation could not be completed."

The * .designer.cs file is populated, but not all assembly references are added to the project; System.Data.Entity needed to be added manually for links to System.Data.Objects files.

I installed Entity Framework 6 Tools for Visual Studio 2012 and 2013 for both versions of Visual Studio. I tried to accomplish this with projects related to both TFS and unrelated ones, and the error persists in any situation.

If I open the solution in Visual Studio 2012, the same errors persist. I can add the * .edmx file in Visual Studio 2010 successfully, and then later open the project in Visual Studio 2013, and the * .edmx file is present and available; it opens and I can view it, but if I go over or edit, I get the following error:

"XmlModels participating in this transaction are not being edited."

Does anyone have any suggestions on this or what might be missing from my environment? I do not understand what is incorrectly configured on my system.

Answer 1

Based on the error "XmlModels participating in this transaction are not being edited," I was able to track the response to a similar problem:

Entity Framework Unable to Update Database Tables in TFS 2010

In short, my project and solution were saved on disk in the folder C: \ Code \ C # \ Application \ [etcetera]

The problem was the "#" symbol in the solution / project / file path. Quickly copying the solution to C: \ Code \ CSharp \ [etcetera] solved the problem of adding and editing an existing * .edmx file.

I answer this to preserve the Wisdom of the Ancients .