Lerning Entity Framework 6 ------ Working with in-memory data

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Sometimes, you need to find some data in an existing context instead of the database. By befault, Entity Framework always find data in database. If you want to find data which have loaded in memory, please do it like this:

Frist of all, let's insert some data for testing:

Then, Write some codes:

class Program
{
    static void Main(string[] args)
    {
        using (MyContext db = new MyContext())
        {
            var person = db.People.Find(1);

            var anotherPersons = db.People.Where(p => p.Age > 0);
            int count = anotherPersons.Count();
        }

        Console.ReadLine();
    }
}

public class Person
{
    public int PersonId { get; set; }

    public int Age { get; set; }

    [MaxLength(50)]
    public string Name { get; set; }
}

public class MyContext:DbContext
{
    public MyContext():base("name=Test")
    {
        DbInterception.Add(new MyCommandInterceptor());
    }

    public DbSet<Person> People { get; set; }
}

class MyCommandInterceptor : DbCommandInterceptor
{
    public override void NonQueryExecuted(DbCommand command, DbCommandInterceptionContext<int> interceptionContext)
    {
        base.NonQueryExecuted(command, interceptionContext);
    }

    public override void ReaderExecuted(DbCommand command, DbCommandInterceptionContext<DbDataReader> interceptionContext)
    {
        base.ReaderExecuted(command, interceptionContext);
        Console.WriteLine("----------------------");
        Console.WriteLine(command.CommandText);
        Console.WriteLine();

    }

    public override void ScalarExecuted(DbCommand command, DbCommandInterceptionContext<object> interceptionContext)
    {
        base.ScalarExecuted(command, interceptionContext);
    }
}

Run the codes, you will find two SQL statments are excuted:

Then, mondify the codes:

static void Main(string[] args)
{
    using (MyContext db = new MyContext())
    {
        var person = db.People.Find(1);

        var anotherPersons = db.People.Local.Where(p => p.Age > 0);
        int count = anotherPersons.Count();
    }

    Console.ReadLine();
}

Run it again:

That's all.