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 d         


        

Answer 1

I've taken some of the previously provided answers and tweaked them to fix a couple of problems:

• Implicitly captured closure

• Key shouldn't be hard coded to "Id"

  public static TEntity Find(this DbSet set, params object[] keyValues) where TEntity : class
  {
      var context = set.GetService();
  
      var entityType = context.Model.FindEntityType(typeof(TEntity));
      var key = entityType.FindPrimaryKey();
  
      var entries = context.ChangeTracker.Entries();
  
      var i = 0;
      foreach (var property in key.Properties)
      {
          var i1 = i;
          entries = entries.Where(e => e.Property(property.Name).CurrentValue == keyValues[i1]);
          i++;
      }
  
      var entry = entries.FirstOrDefault();
      if (entry != null)
      {
          // Return the local object if it exists.
          return entry.Entity;
      }
  
      var parameter = Expression.Parameter(typeof(TEntity), "x");
      var query = set.AsQueryable();
      i = 0;
      foreach (var property in key.Properties)
      {
          var i1 = i;
          query = query.Where((Expression>)
           Expression.Lambda(
               Expression.Equal(
                   Expression.Property(parameter, property.Name),
                   Expression.Constant(keyValues[i1])),
               parameter));
          i++;
      }
  
      // Look in the database
      return query.FirstOrDefault();
  }