EF 6 Codefirst -Setting default value for a property defined in base class using fluent API

Question

I have a base class which has audit properties like

public abstract class BaseModel
{
    [Column(Order = 1)] 
    public long Id { get; set; }
    public long CreatedBy { get; set; }
    public DateTime CreatedDate { get; set; }
    public long ModifiedBy { get; set; }
    public DateTime ModifiedDate { get; set; }
    public bool IsActive { get; set; }
}

All my poco classes derive from this class.

I am trying to set a default value to the IsActive properties. I am not keen on using annotations and hence was wandering if I can work this using fluent API.

I tried this but it does not work. Seems like it creates a new table named BaseModel

modelBuilder.Entity<BaseModel>()
    .Property(p => p.IsActive)
    .HasColumnAnnotation("DefaultValue", true);

Can any one suggest a way here?

http://stackoverflow.com/questions/19554050/entity-framework-6-code-first-default-value — jjj, Jun 19 '15 at 19:11

Marc Cals · Answer 1 · 2015-06-19T18:50:00.047

5

There is no way to do this. It can't set default values with Entity Framework. Instead you can use the constructor

public abstract class BaseModel
{
    protected BaseModel()
    {
        IsActive = true;
    }
}

edited Jun 19 '15 at 18:50

answered Jun 19 '15 at 18:41

Marc Cals

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score 1 · Answer 2 · answered Jan 01 '20 at 11:03

I have resolved this problem by overriding the SaveChanges method. See below for my solution.

Solution Explain

i) Override the SaveChanges method in the DbContext class.

public override int SaveChanges()
{
    return base.SaveChanges();
}

ii) Write logic to set default values

public override int SaveChanges()
{
    //set default value for your property
    foreach (var entry in ChangeTracker.Entries().Where(entry => entry.Entity.GetType().GetProperty("YOUR_PROPERTY") != null))
    {
        if (entry.State == EntityState.Added)
        {
            if (entry.Property("YOUR_PROPERTY").CurrentValue == null)
                entry.Property("YOUR_PROPERTY").CurrentValue = YOUR_DEFAULT_VALUE;
        }
    }

    return base.SaveChanges();
}

Example

i) Create Base Class

  public abstract class BaseModel
  {
       [Column(Order = 1)] 
       public long Id { get; set; }
       public long CreatedBy { get; set; }
       public DateTime CreatedDate { get; set; }
       public long ModifiedBy { get; set; }
       public DateTime ModifiedDate { get; set; }
       public bool IsActive { get; set; }
  }

ii) override SaveChanges

public override int SaveChanges()
{

    //set default value for IsActive property
    foreach (var entry in ChangeTracker.Entries().Where(entry => entry.Entity.GetType().GetProperty("IsActive") != null))
    {
        if (entry.State == EntityState.Added)
        {
            if(entry.Property("IsActive").CurrentValue == null)
                entry.Property("IsActive").CurrentValue = false;
        }
    }

    return base.SaveChanges();
}

EF 6 Codefirst -Setting default value for a property defined in base class using fluent API

2 Answers2