Compare Dates using LINQ to Entities (Entity Framework)

Adding existing entities to a collection on a newly built object using the entity framework

"Attach" is not allowed because you haven't saved the order yet. Calling "Add" tells Entity Framework that you want to insert a new contact. So you are left with only one option. You need to load the contact....Here's the fastest way to do that:...OrderDetails context = new OrderDetails(); Contact contact = context.GetObjectByKey(new EntityKey("Ord...

LINQ query or GetObjectKey to get single Entity Framework entities?

I prefer the latter because it is explicitly clear what it is you want. By using EntityKey (and this is something that the ADO.NET team doesn't seem to understand), we have to work around the structure imposed on us by Entity Framework. By using the query language in the way you did in the second example, we're telling all of the rest of the deve...

How should two entity framework entities be compared?

Override the Equals method of your object and write an implementation that compares the properties that make it equal. ... public override bool Equals(object obj) { return MyProperty == ((MyObject)obj).MyProperty }

LINQ to Entities only supports casting in the Entity Framework. basic kinds in the Entity Data Model

The Entity Framework makes this difficult and I'm not sure there's a way to do what you want to do with a single return value type (IComparable, object, etc). You might consider reworking your design into a dictionary of name-to-...Func<IQueryable<K>, IOrderedQueryable<K>>... values:..._possibleSortForForumItem.Add("CreateDate", query => query...

Linq to Entities vs. Linq to SQL vs. Entity Framework

There are two ways of writing queries with Entity Framework:...Linq to Entities ( ...http://msdn.microsoft.com/en-us/library/bb386964.aspx... )...Entity SQL ( ...http://msdn.microsoft.com/en-us/library/bb387145.aspx... )...L2E is not a separate technology, but rather a part of EF....Have a look at this article for a comparison: ...http://thedatafar...

The LINQ expression node type 'Invoke' is not supported in the entity framework's LINQ to Entities.

This problem can be solved using the AsExpandable() method present in LINQKIT by Joe Albahari. He's the same creator of ...PredicateBuilder... that I see you're using....If querying with Entity Framework, change the last line to this:...return objectContext.Products.AsExpandable().Where(predicate);...You can grab LINQKIT DLL ...here... or install i...

how to use entity framework to group by date not date with time

Use ...EntityFunctions.TruncateTime... Method (...Nullable<DateTime>...).... It will be transalated into ...TRUNCATETIME()... TSQL function in generated SQL query, which does what you need:...Returns the expression, with the time values truncated....So your code should be as follows:...//get data var myData = from log in db.OperationLogs ...

How can I compare a nullable type date using user entered date?

Some .NET operations can not be implicitly converted to equivalent SQL operations, for these you need to use the methods provided in ...System.Data.Entity.DbFunctions.... In your specific example, you should try using the ...TruncateTime... method instead of accessing ....Date... property of the ...DateTime... instance....Example:...var date = use...

Best way to compare date in Entity Framework

You can use ...DbFunctions.TruncateTime... canonical function like this...var entity = dbContext.MyTable .Where(w => w.PId == 3 && DbFunctions.TruncateTime(w.CreatedOn) == mydate.Date) .First();

Getting all dates between two dates using datepickers and Entity Framework 6

The cause of your error message...You should be aware about the differences between ...IEnumerable... and ...IQueryable.......An object of a class that implements ...IEnumerable... holds everything to enumerate over the sequence of items it represents. You can ask for the first item of the sequence, and once you've got one, you can ask for the next...