How to have default values for an attribute in Code First? - asp.net

Question

Basically I'm trying to expand on the already created SimpleMembership of ASP.NET MVC 4.
I wanna add a balance field that has the initial value of 0.
I've tried with the following code and inserting nothing in the Balance field:
[Table("UserProfile")]
public class UserProfile
{
[Key]
[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
public int UserId { get; set; }
public string UserName { get; set; }
public string RealName { get; set; }
public int Balance { get; set; }
}
But unfortunately I get an exception when I try to create a new user (without a balance) that I cannot insert null in balance since it doesn't allow nulls.
How can I get balance to be 0 as a default value in Code First.

Answer 1

The
int Balance
does not allow nulls but
int? Balance
does.
If you want to controll the structure at the database level, use explicit migrations and manually tweak the generated migration code so that you set up a default value at the database level. If you want a default value at the code level, just set the value in the default constructor of the class.

Answer 2

First: You can use a constructor like this:
[Table("UserProfile")]
public class UserProfile
{
[Key]
[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
public int UserId { get; set; }
public string UserName { get; set; }
public string RealName { get; set; }
public int Balance { get; set; }
public UserProfile()
{
this.Balance = 0;
}
}
Second, clean and rebuild solution, then use the migration command
Update-database -verbose

Answer 3

Integers have a default value of 0 by default. When you instantiate a new UserProfile, Balance should already be set to 0.
See: Default Values Table (C# Reference)