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Alex, I have enjoyed perusing through your tips and wanted to request a post on serialization. I recently switched from L2S to EF and now considering switching back because of serialization issues.

Primarily, when using L2S, I could serialize the returned object as JSON (or XML for that matter) and get simply: { "Id":1, "Name":"John Doe" } but after switching to EF I am stuck with { "Id":1, "Name":"John Doe", "EntityState":"...", "EntityKey":"...", ... }

And the work around to fetch and return objects as Anonymous: (from ... where ... select new { Id : t.Id, Name : t.Name }).First(); which is obviously undesirable because it means having to specify each field and is quite rigid by design. Any best practices or recommendations?

Well as it turns out the quick way around it is to return anonymous objects instead of entity objects and use projections.

> philha@microsofxxxxx wrote:

> The general approach we recommend is to control the object you're sending to the browser. Instead of sending the full object you grabbed from the db, you want to perhaps send a projection. For example:

>

> Instead of

>

>        var product = db.Products.Single(...);

>        return View(product);

>

> You could send an anonymous object with only the fields you want...

>

>        var product = db.Products.Single(...);

>      var jsonProduct = new {Name = product.Name, Price = product.Price};

>        return View(product);

Not fond of that approach because it requires extra housekeeping (update projects if db schema or field names change and require explicitly specifying all fields). I've fallen back on EFPocoAdapter for now.

Thanks for pointing out the comment spam. Haven't used that blog for years. Cleaned up and updated link.

The Problem: In some of earlier tips we talked about using Attach to load things into the ObjectContext

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This is 20th post in my ongoing series of Entity Framework Tips . Fixed Length Field Padding: If you

This is the 19th post in my ongoing series of Entity Framework Tips . Background: If you have a table

The Problem: In some of earlier tips we talked about using Attach to load things into the ObjectContext

Congrats for this serie of posts Alex, they're great!

I'm learing a lot with them, keep up the good work.

Regards!

To Aleem question: This is a solution starter. I did not cover navigations because of infinite recursion.

public static string SerilaizeJSON(this EntityObject entity)

{

   StringBuilder sb = new StringBuilder(200);

   PropertyInfo[] propertyInfos = entity.GetType().GetProperties();

   Type scalarPropertyType = typeof(EdmScalarPropertyAttribute);

   sb.Append("{\"" + entity.GetType().Name + "\" : {");

   foreach (PropertyInfo p in propertyInfos) {

       if (p.GetCustomAttributes(scalarPropertyType, false).Count > 0) {

           sb.AppendFormat("\"{0}\" : \"{1}\",", p.Name, p.GetValue(entity, null));

       }

   }

   if (propertyInfos.Count > 0) {

       sb.Remove(sb.Length - 1, 1);

   }

   sb.Append("}}");

   return sb.ToString();

}

Hi,

We have a User entity type mapped to a table named tbl_user_profile. This has fields like firstname, lastname, etc. Another entity type Coordinator is mapped to tbl_coordinator. The table has a FK name user_id pointing to the tbl_user_profile table. All coordinators are users but the reverse is not true. The framework we use, expects all fields in the same class and hence, we want all fields of the coordinator in the coordinator entity type. We will not use inheritance because we use RIA domain services which does not support inheritance.

To achieve this, we added the tbl_user_profile table in the mapping for Coordinator entity type. While doing this we get following error :

"EntitySets 'Users' and 'Coordinators' are both mapped to table 'tbl_user_profile'. Their Primary Keys may collide".

Error 1 Error 3033: Problem in Mapping Fragment starting at line 2016: EntitySets 'Users' and 'Coordinators' are both mapped to table 'tbl_user_profile'. Their Primary Keys may collide.

E:\EDMX\EntityModel.edmx 2017 15 MyTrial.Data

"User" has entityset named "Users" and "Coordinator" has entityset named "Coordinators".

What is the cause and solution to this problem. Any way to work around it?

Thanks,

Yash