CODEWITHSUNDEEP
linqentity-frameworklambdalinq-to-entities
Ramesh Bolla
Ramesh Bolla

Reputation: 412

Lambda Expression for LINQ Select Items

I have this code

var list = _db.Projects.Where(item => item.Loc =="IN").Select(p => new {id=p.Id, title=p.Title,pc=p.PostalCode });

Project table having lot of columns, i need to query required columns dynamically and load from database, not all columns along with data.

Questions:

  1. how to write lambda expressions for linq select ?
  2. How to reduce data reads on database by selecting specific cols, entity framework ?

Upvotes: 3

Views: 8883

Answers (1)

usr
usr

Reputation: 171236

Look at the expression the C# compiler generated and try to replicate what it does:

Expression<Func<Project, object>> lambda =
    (Project p) => (object)new {id=p.Id, title=p.Title,pc=p.PostalCode };

I hope this code compiles. If not, you'll surely be able to fix it. Afterwards, look at the contents of the lambda variable.

Note, that the cast to object is only there to make this compile. You don't need/want that is production.

Upvotes: 1

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