entity-framework-4 - w3toppers.com

Is it possible to prevent EntityFramework 4 from overwriting customized properties?

A different approach is to hook into the ObjectMaterialized event in the DbContext and set the kind there. In my DbContext constructor, i do this: ((IObjectContextAdapter)this).ObjectContext.ObjectMaterialized += new ObjectMaterializedEventHandler(ObjectMaterialized); and then the method looks like this: private void ObjectMaterialized(object sender, ObjectMaterializedEventArgs e) { Person person = e.Entity as Person; if (person != null) // the … Read more

How to use Entity Framework to map results of a stored procedure to entity with differently named parameters

From Entity Framework Code First book (page 155): The SQLQuery method always attempts the column-to-property matching based on property name… None that the column-to-property name matching does not take any mapping into account. For example, if you had mapped the DestinationId property to a column called Id in the Destination table, the SqlQuery method would … Read more

Annotating properties on a model with default values

I don’t know if this will satisfy your DRY needs, but it’s a start I think. I would rework the model a bit like this: public class Person { private const int DEFAULT_AGE = 18; private int _age = DEFAULT_AGE; [DefaultValue(DEFAULT_AGE)] public int Age { get { return _age; } set { _age = value; … Read more

Entity Framework initialization is SLOW — what can I do to bootstrap it faster?

In pre EF6 view generation is known to be slow for bigger models. For now the solution is to use pregenerated views. This way you generate views at design time and are avoiding this work at runtime. To do that download EF power tools and select “Optimize Entity Data Model”. It will add a C# … Read more

Add the where clause dynamically in Entity Framework

You can use a beautiful thing called PredicateBuilder. Use it like this var pr = PredicateBuilder.False<User>(); foreach (var name in names) { pr = pr.Or(x => x.Name == name && x.Username == name); } return query.AsExpandable().Where(pr);

Map two different entities to the same table?

You can’t map two regular entities into same table. You have several choices: Use table splitting. Use custom query with projection to non entity type (as @Aducci proposed) Use QueryView Use database view or directly DefiningQuery Table splitting Table splitting allows you to map a table into two entities in 1:1 relation. First entity will … Read more

Entity Framework Code First AddOrUpdate method insert Duplicate values

Ok I was banging my face off the keyboard for an hour with this. If your table’s Id field is an Identity field then it won’t work so use a different one for identifierExpression. I used the Name property and also removed the Id field from the new Hall {…} initializer. This tweak to the … Read more

The object ‘DF__’ is dependent on column ‘’ – Changing int to double

Try this: Remove the constraint DF_Movies_Rating__48CFD27E before changing your field type. The constraint is typically created automatically by the DBMS (SQL Server). To see the constraint associated with the table, expand the table attributes in Object explorer, followed by the category Constraints as shown below: You must remove the constraint before changing the field type.

Entity Framework – default values doesn’t set in sql server table

This is one of the few issues that are problematic with Entity Framework. Say you have a class that looks like this: public class MyEntity { // Id is a PK on the table with Auto-Increment public int Id { get; set; } // CreatedOn is a datetime, with a default value public DateTime CreatedOn … Read more

Using Entity Framework with an SQL Compact Private Installation

I figured out how to do it, thanks to a blog post by Steve Lasker. Basically, here is what you have to do: (1) Set a reference to System.Data.SqlServerCe.dll in your project. Set the CopyLocal property to True. (2) In the App.config for your project, add the following XML markup. It tells EntityFramework to look … Read more