Does EF Core SaveChanges validate against the data annotations

c# data-annotations entity-framework-core

Question

I have a model with Data Annotations and I was wondering if it was possible to have the SaveChanges method fail if the Data Annotation failed?

I was expecting SaveChanges to throw an exception along the lines of "Test2 is outside the Range of 2 to 4". Instead, it saves into the database.

For example, here's my test entity:

public class Visit
{
    public int Id { get; set; }

    [MaxLength(2)]
    public string Test { get; set; }

    [Range(2, 4)]
    public int Test2 { get; set; }
}

Here's the Context:

public class Context : DbContext
{
    public Context()
    {

    }

    public Context(DbContextOptions<Context> options)
            : base(options)
    {
    }

    public DbSet<Visit> Visits { get; set; }
}

And here's the very simple MVC Controller method that I'm using to test it with:

public HomeController(Context context)
    {
        context.Visits.Add(new Visit() {Test = "21", Test2 = 3423});
        var results = context.SaveChanges();
    }

Here's my project.json file:

{
  "dependencies": {
    "Microsoft.AspNetCore.Diagnostics": "1.0.0",
    "Microsoft.AspNetCore.Mvc": "1.0.0",
    "Microsoft.AspNetCore.Razor.Tools": {
      "version": "1.0.0-preview2-final",
      "type": "build"
    },
    "Microsoft.AspNetCore.Server.IISIntegration": "1.0.0",
    "Microsoft.AspNetCore.Server.Kestrel": "1.0.0",
    "Microsoft.AspNetCore.StaticFiles": "1.0.0",
    "Microsoft.EntityFrameworkCore.SqlServer": "1.0.0",
    "Microsoft.EntityFrameworkCore.Tools": "1.0.0-preview2-final",
    "Microsoft.Extensions.Configuration.EnvironmentVariables": "1.0.0",
    "Microsoft.Extensions.Configuration.Json": "1.0.0",
    "Microsoft.Extensions.Logging": "1.0.0",
    "Microsoft.Extensions.Logging.Console": "1.0.0",
    "Microsoft.Extensions.Logging.Debug": "1.0.0",
    "Microsoft.Extensions.Options.ConfigurationExtensions": "1.0.0",
    "Microsoft.NETCore.App": {
      "version": "1.0.0",
      "type": "platform"
    },
    "Microsoft.VisualStudio.Web.BrowserLink.Loader": "14.0.0",
    "System.ComponentModel.Annotations": "4.1.0"
  },

  "tools": {
    "Microsoft.EntityFrameworkCore.Tools": "1.0.0-preview2-final",
    "BundlerMinifier.Core": "2.0.238",
    "Microsoft.AspNetCore.Razor.Tools": "1.0.0-preview2-final",
    "Microsoft.AspNetCore.Server.IISIntegration.Tools": "1.0.0-preview2-final"
  },

  "frameworks": {
    "netcoreapp1.0": {
      "dependencies": {
      },
      "imports": [
        "dotnet5.6",
        "portable-net45+win8"
      ]
    }
  },

  "buildOptions": {
    "emitEntryPoint": true,
    "preserveCompilationContext": true
  },

  "runtimeOptions": {
    "configProperties": {
      "System.GC.Server": true
    }
  },

  "publishOptions": {
    "include": [
      "wwwroot",
      "Views",
      "Areas/**/Views",
      "appsettings.json",
      "web.config"
    ]
  },

  "scripts": {
    "prepublish": [ "bower install", "dotnet bundle" ],
    "postpublish": [ "dotnet publish-iis --publish-folder %publish:OutputPath% --framework %publish:FullTargetFramework%" ]
  }
}
1
1
9/14/2016 3:01:19 PM

Accepted Answer

According to a github issue related to this question, Entity Framework Core does not perform automatic data validations.

There's a somewhat updated list of features present in EF6 that aren't in Core here.

2
9/15/2016 4:24:54 PM

Popular Answer

You can implement your own validation by overriding SaveChanges:

class Context : DbContext
    {
        public override int SaveChanges()
        {
            var entities = from e in ChangeTracker.Entries()
                           where e.State == EntityState.Added
                               || e.State == EntityState.Modified
                           select e.Entity;
            foreach (var entity in entities)
            {
                var validationContext = new ValidationContext(entity);
                Validator.ValidateObject(entity, validationContext);
            }

            return base.SaveChanges();
        }
    }

This will validate against your data annotations and throw an exception if the validation fails.



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