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c#entity-framework
Obl Tobl
Obl Tobl

Reputation: 5684

Attribute for "Property not updateble"

I have an application (webservice), where numerous objects are inserted into a database or updated (with Entity Framework), but never read. So I even don't have read-access to this database.
Now a new requirement wants some properties to be inserted but never to be updated. I save all objects like this:

Type t = obj.GetType();
db.Set<TT>().AddOrUpdate(MapObject<TT>(obj)); //Maps to database entity and saves object

Now the question is, if there is an attribute I can tell a property to be inserted, but ignored while updating? In best case something like this:

[InsertOnly]
public string SomeText { get; set; }

Upvotes: 1

Views: 196

Answers (2)

Morten Bork
Morten Bork

Reputation: 1632

You can add a custom attribute.

public class InsertOnly : Attribute
{}

If we consider

on your EF object, you add the custom property as such:

public class SomeEFClass {
       [InsertOnly]
       public int Id {get;set;}
   }

Then change 

db.Set<TT>().AddOrUpdate(MapObject<TT>(obj)); //Maps to database entity and

To include something like (This is pseudo code, don't expect it to run)

foreach(Property info pi in t.GetProperties())
{
    if(pi.GetCustomAttribute<InsertOnly>() == null)
    {
        //You can safely update this property
    }
    else
    {
        //This property is only for inserting
    }
}

I am uncertain if you can add the custom attribute via partial class overloading of a property? That might be worth a shot?

Upvotes: 0

Afshar
Afshar

Reputation: 11543

In your unit of work save routine, check ChangeTracker and remove those records or properties that are marked as update. Something like this:

var modifiedItems = _dbContext.ChangeTracker.Entries()
    .Where(x => x.State == EntityState.Modified)
    .ToList();

EntityState has following types:

  • Detached
  • Unchanged
  • Added
  • Deleted
  • Modified

Upvotes: 1

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