Can't open EDMX-file in designer

Question

It opens as XML file only. In MS VS 2010 Ultimate + SP1.

I need to open it in model-designer.

What can I do??

Answer 1

On the file in the solution explorer try

Right Click > Open With > ADO.NET Entity Data Model Designer

Answer 2

I've came across the same problem in Visual Studio 2015,i tried to open the file with

Right Click > Open With > ADO.NET Entity Data Model Designer 

and the option is not there.From there i realized my installation of Visual Studio 2015 must be without some components, so i went back to setup and installed Microsoft SQL Server Data Tools and Microsoft Web Developer Tools.Finally it worked ! The options are there when you open from solution and the file can be opened

Components that i added

Answer 3

Adds references to the System.Data, System.Data.Entity, System.Core, System.Security, and System.Runtime.Serialization assemblies to the project, if they do not already exist.