Entity Framework: Deleting multiple objects query

Question

I have a List which hold the PK ID's of a number of objects in a collection that I want to remove. Does anyone know how to write a single query to retrieve these objects?

Eg:

IList<int> objectList; // populated with int Primary key Ids

using (MyEntities context = new MyEntities()){

    var result = context.MyObjectCollection.Where(obj=> obj.ID IN objectList);

    foreach(var item in result){
        context.DeletObject(item);
    }
    context.SaveChanges();
}

Any help would greatly be appreciated!

Answer 1

var result = context.MyObjectCollection.Where(obj=> objectList.Contains(obj.ID));

Answer 2

Mel's answer doesn't work because in .NET 3.5 SP1 the EF doesn't know how to translate list.Contains(...) into T-SQL. Although this is coming in 4.0.

The workaround is to manually produce a big OR query i.e.

Where(obj => obj.ID == item1 || obj.ID == item2 ....)

Here is a tip I wrote that makes that easy:

Tip 8 - How to write where IN style queries using LINQ to Entities

Hope this helps

Alex James

Entity Framework Team - Read my Entity Framework Tips

Answer 3

http://efe.codeplex.com

this.Devices.Update(o => new Device() { LastOrderRequest = DateTime.Now, Description = "teste" }, o => o.Id == 1);