Visual Studio 2017, .NET Core, MVC and EF on Mac

I’ve started playing with Visual Studio 2017 on the Mac, pulling across a sample MVC Core + Entity Framework Core tutorial project on the Microsoft site. The tutorial can be found here.

I run a Windows in a VirtualBox VM on the Mac, so I have a full Windows 10 + VS 2017 Community install with MSSQL 2016 on it.

On the Mac side, I was trying the latest VS 2017 Community for Mac, along with ASP.NET Core.

I was hoping to suss out how much cross-platform compatibility there was, and how much of a poor cousin VSMac was compared to its Windows counterpart, which is still one of my favourite IDEs.


Installing VSMac is pretty straightforward and .NET Core is a separate install documented on the Microsoft website.

Moving the project over to the Mac side

I started and finished the project on the Windows VM, running on MS Sql Server. This project opens up fine on VSMac. I had some high expectations it would, and it does. It even builds and runs!

Of course, the lack of database access on the Mac side needed to be addressed, but the web project hosted inside VSMac started up and ran just fine in Safari using localhost and a custom port number just as in the Windows VM and Edge.

Converting to use MySQL instead of SQL Server would be the next challenge.

Adding Pomelo for MySQL Support

I didn’t find too many options for MySQL. There are some hints on the MySQL blog that MySQL Connector works with Core, but I couldn’t actually find a package for the Mac listed in their downloads so I gave up. The one that looked OK is Pomelo.

Pleasantly enough, Pomelo.EntityFrameworkCore.MySql  is one of the packages listed when firing up the Project | Add NuGet Packages… option in VSMac.

Simply add the package to your project at this point and you’re almost ready to go.

Changing the Entity Framework Provider to MySQL

This was also fairly straightforward. In the Startup.cs file, the database context needs to be adjusted to use MySQL.


public void ConfigureServices(IServiceCollection services)
  // Add framework services.

  services.AddDbContext<WebTestContext>(options => options.UseSqlServer(Configuration.GetConnectionString("WebTestContext")));


public void ConfigureServices(IServiceCollection services)
   // Add framework services.

  services.AddDbContext<WebTestContext>(options => options.UseMySql(Configuration.GetConnectionString("WebTestContext")));

The connection string in the appsettings.json was also changed to the MySQL flavour:

 "ConnectionStrings": {
 "WebTestContext": "server=localhost;port=8889;database=thedbname;uid=myuserid;pwd=thepassword"

Once this was done, running

   dotnet ef update

on the terminal command line in the project directory (where the .csproj file is located) should attach to the configured MySQL instance and create the required tables (in this case, just one) for the sample project.

And voila – things run and the database is created. Quite impressive. You can even add a new movie. But alas, not a second movie…because…

Add Auto Increment to ID field in MySQL

For some reason, the Pomelo provider, or .NET, or something somewhere doesn’t know that EF relies on the ID field on the table being an auto incrementing field. This causes any table inserts beyond the first item to fail with a MySqlException: Duplicate entry ‘0’ for key ‘PRIMARY’error.

The fix is simple enough; either:

  1. Go into phpMyAdmin and change the row property for the ID column to check the A_I (Auto_Increment) box, then save changes; or
  2. Run a SQL command to do the same thing – something along the lines of


  1. Entity Framework Core references must be added manually when using VSMac – you can’t add this through NuGet right now. The .csproj file must be edited manually to create the references. This appears to be a bug / limitation with just VSMac. Since I started the project on VSWin and moved to VSMac, I didn’t have this problem. But I did with a new project started on VSMac. I suspect that moving back and forth between the environments may be quite feasible.
  2. Scaffolding for helping create Insert / Update / Create views does not appear to be present for VSMac while VSWin has an option to create an MVC Controller along with associated views. These would be really handy to help build out your basic CRUD functionality. However, there may be options using Yeoman. More to come.
  3. Razor view tag helpers do not seem to provide syntax highlighting in VSMac.

Next Steps

More research to come, but the next step will be configuring the project so it runs nicely under NGINX or Apache as a Kestrel reverse proxy on the Mac without Visual Studio hosting.