How to Use enum with Entity Framework 5 ?

What is enum ?

• The enum keyword is used to declare an enumeration
• A distinct type consisting of a set of named constants called the enumerator list
• Every enumeration type has an underlying type
• The default underlying type of the enumeration elements is int
• By default, the first enumerator has the value 0
• And the value of each successive enumerator is increased by 1
• EF 5 enum can have the Types as  Byte, Int16, Int32, Int64 or SByte

Let's Take a Simple Example

E.g. 1 :

enum Days {Sat, Sun, Mon, Tue, Wed, Thu, Fri};

In this enumeration, Sat is 0, Sun is 1, Mon is 2, and so forth

E.g. 2 : Enumerators can have initializers to override the default values

enum Days {Sat=1, Sun, Mon, Tue, Wed, Thu, Fri};

In this enumeration, the sequence of elements is forced to start from 1 instead of 0


How to Use enum with Entity Framework 5 Code First ?

• This feature is Latest improvement of EF 5

Step 1 : Open Visual Studio 2012

Step 2 : File ==> New Project as EF5EnumSupport

Step 3 :  Right Click Your Solution and then Click Manage NuGet Packages... 

Step 4 : Click Online Tab and Then Type Entity Framework 5 on Search Box

            After that Select EntityFramework and Click Install 

Step 5 : Click I Accept

After the above Step, below mentioned DLLs (Red Color)  have added to the Project

Step 6 : Add ==> New Class and make it as enum Type Course

Course.cs

 namespace EF5EnumSupport.Models

 {

    public enum Course

    {

        Mcsd = 1,

        Mcse,

        Mcsa,

        Mcitp

    }

 }

Step 7 : Add ==> New Class as Student

Student.cs

 namespace EF5EnumSupport.Models

 {

    public class Student

    {

        public int Id { get; set; }

        public string Name { get; set; }

        public Course Course { get; set; }

    }

 }

Step 8 : Create DbContext derived Class as StudentContext

StudentContext.cs

 using System.Data.Entity;

 namespace EF5EnumSupport.Models

 {

    public class StudentContext : DbContext

    {

        public DbSet<Student> Students { get; set; }

    }

 }

Step 9 : Console application's Main Method is as below

Program.cs

using System;

using System.Linq;

using EF5EnumSupport.Models;

namespace EF5EnumSupport

{

  public class Program

  {

     static void Main(string[] args)

     {

       using (var context = new StudentContext())

       {

        context.Students.Add(new Student { Name = "Sampath Lokuge",

                                           Course = Course.Mcsd });

        context.SaveChanges();

         var studentQuery = (from d in context.Students

                             where d.Course == Course.Mcsd

                             select d).FirstOrDefault();

         if (studentQuery != null)

          {

           Console.WriteLine("Student Id: {0} Name: {1} Course : {2}",

                            studentQuery.Id, studentQuery.Name,

                            studentQuery.Course);

           }

         }

     }

  }

}

The brand new enum support allows you to have enum properties in your entity classes

Step 10 : Run the Console Application

               

               DEBUG ==> Start Without Debugging (Ctrl + F5)

Step 11 :  Where's the Database ?

• By default the database will be created on the LocalDB instance
• The Entity Framework names the database after the fully qualified name of the derived context
• i.e. EF5EnumSupport.Models.StudentContext
  
  
  SQL Server Object Explorer in Visual Studio 2012 is as below 
  
  
   
  

 

          View Data on Students Table

      

    What is LocalDb ?

• Microsoft SQL Server 2012 Express LocalDB is an execution mode of SQL Server Express targeted to program developers
• LocalDB installation copies a minimal set of files necessary to start the SQL Server Database Engine                        

That's It.You're Done.

Conclusion

• Entity Framework 5 brings a number of improvements and enum Support in Code First is one of them
• You can see that when you use enum type with your model class, Visual Studio 2012 gives  intellisense support out of the box
• It's really awesome new feature of the Entity Framework 5
• Enjoy it

I hope this helps to You.Comments and feedback greatly appreciated.

If you feel it was a good article,Give me a +1.Thank You.

Happy Coding.


Another Article about Entity Framework 5

What is New in Entity Framework 5 ?

CodeProject