DbSet doesn't have a Find method in EF7

Question

I am trying to create a generic repository to access my database. In EF6 I was able to do that in order to get a specific entity:

protected IDbSet<T> dbset;  public T Get(object id) {     return this.dbset.Find(id); } 

DbSet in EF7 is missing a Find method. Is there a way to implement the above piece of code?

Answer 1

Here's a very crude, incomplete, and untested implementation of .Find() as an extension method. If nothing else, it should get you pointed in the right direction.

The real implementation is tracked by #797.

static TEntity Find<TEntity>(this DbSet<TEntity> set, params object[] keyValues)     where TEntity : class {     var context = ((IAccessor<IServiceProvider>)set).Service.GetService<DbContext>();      var entityType = context.Model.GetEntityType(typeof(TEntity));     var key = entityType.GetPrimaryKey();      var entries = context.ChangeTracker.Entries<TEntity>();      var i = 0;     foreach (var property in key.Properties)     {         var keyValue = keyValues[i];         entries = entries.Where(e => e.Property(property.Name).CurrentValue == keyValue);         i++;     }      var entry = entries.FirstOrDefault();     if (entry != null)     {         // Return the local object if it exists.         return entry.Entity;     }      // TODO: Build the real LINQ Expression     // set.Where(x => x.Id == keyValues[0]);     var parameter = Expression.Parameter(typeof(TEntity), "x");     var query = set.Where((Expression<Func<TEntity, bool>>)         Expression.Lambda(             Expression.Equal(                 Expression.Property(parameter, "Id"),                 Expression.Constant(keyValues[0])),             parameter));      // Look in the database     return query.FirstOrDefault(); } 

Answer 2

In case you are using EF 7.0.0-rc1-final, below you find a small update for the code presented by @bricelam in the previous answer. By the way, thank you very much @bricelam - your code was extremely useful for me.

Here are my dependencies under "project.config":

"dependencies": {     "EntityFramework.Commands": "7.0.0-rc1-final",     "EntityFramework.MicrosoftSqlServer": "7.0.0-rc1-final",     "Microsoft.Framework.Configuration.Json": "1.0.0-beta8",     "Microsoft.Framework.ConfigurationModel": "1.0.0-beta4",     "Microsoft.Framework.ConfigurationModel.Json": "1.0.0-beta4",     "Microsoft.Framework.DependencyInjection": "1.0.0-beta8" } 

And below is the extension method for DbSet.Find(TEntity):

using Microsoft.Data.Entity; using Microsoft.Data.Entity.Infrastructure; using System; using System.Linq; using System.Linq.Expressions;  namespace Microsoft.Data.Entity.Extensions {     public static class Extensions     {         public static TEntity Find<TEntity>(this DbSet<TEntity> set, params object[] keyValues) where TEntity : class         {             var context = ((IInfrastructure<IServiceProvider>)set).GetService<DbContext>();              var entityType = context.Model.FindEntityType(typeof(TEntity));             var key = entityType.FindPrimaryKey();              var entries = context.ChangeTracker.Entries<TEntity>();              var i = 0;             foreach (var property in key.Properties)             {                 entries = entries.Where(e => e.Property(property.Name).CurrentValue == keyValues[i]);                 i++;             }              var entry = entries.FirstOrDefault();             if (entry != null)             {                 // Return the local object if it exists.                 return entry.Entity;             }              // TODO: Build the real LINQ Expression             // set.Where(x => x.Id == keyValues[0]);             var parameter = Expression.Parameter(typeof(TEntity), "x");             var query = set.Where((Expression<Func<TEntity, bool>>)                 Expression.Lambda(                     Expression.Equal(                         Expression.Property(parameter, "Id"),                         Expression.Constant(keyValues[0])),                     parameter));              // Look in the database             return query.FirstOrDefault();         }     } }