How do you create a visual model of EntityFramework code first

Question

If you look here you will notice that this guy is showing the Entity Model Diagrams, I would like to know how I can create an Entity Model Diagram from my EntityFramework code first classes.

It just gets frustrating trying to remember how everything links together just by looking at the code.

Solution 1

With the Entity Frameworks Power Tools installed you can right-click the context in your solution view, click on "Entity Framework", then select "View Entity Data Model".

This will create a neat diagram from your classes.

Solution 2

An Entity Data Model Diagram is just a visual display of an EDMX file. In order to get such a diagram from a Code-First model you must create an EDMX file from it:

using System.Data.Entity.Infrastructure; // namespace for the EdmxWriter class

using (var ctx = new MyContext())
{
    using (var writer = new XmlTextWriter(@"c:\Model.edmx", Encoding.Default))
    {
        EdmxWriter.WriteEdmx(ctx, writer);
    }
}

This code creates a file Model.edmx that you can open in Visual Studio. It will display the model diagram. The EDMX file is a snapshot of your current Code-First model. When you change the model in code you must create a new EDMX file to reflect those changes in the diagram.

Solution 3

In addition to Slauma his answer. If you want to be able to adjust the layout of the diagram and you dont want to redo this every time again after creation, you can copy the Diagram node from the previously EDMX file into the new EDMX file:

        string sPath = @"c:\Development\{0}";
        try
        {
            File.Copy(String.Format(sPath, "Model.edmx"), String.Format(sPath, "ModelTemplate.edmx"));
            File.Delete(String.Format(sPath, "Model.edmx"));
        }
        catch (Exception)
        {

            //no worry, file not found issues
        }

        using (var ctx = new ShopID.Models.ShopIDDb())
        {
            using (var writer = new XmlTextWriter(String.Format(sPath, "Model.edmx"), Encoding.Default))
            {
                EdmxWriter.WriteEdmx(ctx, writer);
            }
        }

        XmlDocument oldModel = new XmlDocument();
        oldModel.Load(String.Format(sPath, "ModelTemplate.edmx"));
        XmlDocument newModel = new XmlDocument();
        newModel.Load(String.Format(sPath, "Model.edmx"));

        var nsmgr = new XmlNamespaceManager(newModel.NameTable);
        nsmgr.AddNamespace("diagram", "http://schemas.microsoft.com/ado/2009/11/edmx");
        XmlNode node = oldModel.SelectSingleNode("//diagram:Diagrams", nsmgr).ChildNodes[0];
        XmlNode newNode = newModel.SelectSingleNode("//diagram:Diagrams", nsmgr);
        XmlNode importNode = newNode.OwnerDocument.ImportNode(node, true);
        newModel.ImportNode(importNode, true);
        newNode.AppendChild(importNode);
        newModel.Save(String.Format(sPath, "Model.edmx"));
        File.Delete(String.Format(sPath, "ModelTemplate.edmx"));

//Updated model is ready to be opened with Visual Studio

Comments

[Callum Linington]

That was exactly what I was looking for, couldn't quite remember the name!

[StefanG]

Simple and clean! Entity Framework Power Tools would be my first choice, but they are painful to use for complex projects.

[Ehsan88]

Don't forget to run Visual Studio as administrator so that you could able to create the .edmx file

[Efrain]

Unfortunately this extension is not supported in VS2015 anymore. :(

[Julio Nobre]

You can get an updated version of Entity Framework power tools 4 beta for visual studios 2010 - 2015 at GitHub (github.com/lastlink/EFPowerToolsExample). I would also suggest to Dennis Traub to consider updating his answer's link. That could prevent us from regular digging. Anyway, Dennnis, thanks a lot for poiting it out this great tool.

[Ian]

Used this for a bit and then realised that any entities/associations added to the model are not drawn in the updated one, as the corresponding diagram nodes are missing. Here's what I do now:

[patsy2k]

how can you call this code from visual studio? where should i put it?

[Bob.at.Indigo.Health]

Ok... I'm going to guess that the link in the answer (marketplace.visualstudio.com/…) installs something that doesn't work with the latest EF Core stuff in the latest VS 2019 (v16.4.5), because when I try to View Entity Data Model (Read-Only) it complains that it can't find a constructable class that derives from DbContext, despite the fact that the file contains public class ApplicationDbContext : IdentityDbContext {…}

[tobbenb3]

Tried this, but it did not help, unfortunately: stackoverflow.com/questions/18470595/…