LINQ to Entities does not recognize the method 'Boolean IsNullOrWhiteSpace(System.String)' method

 

recently I have used below query to get some filterded details from my table.

dbContext.ttable.Where(r => string.IsNullOrWhiteSpace(r.field))

but when I try to run above code snipped I got

“LINQ to Entities does not recognize the method 'Boolean IsNullOrWhiteSpace(System.String)' method, and this method cannot be translated into a store expression."”

after few minutes searching found the reason for that.

My query return type is IQueryable<ttable>.So this type is optimized to the deliver an optimized query.In this context all C# methods are not supported.There for I have to change the query like this and then it works

dbContext.table.where.(!(b.field == null || r. b.field.Trim() == ""))