Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers. We don’t allow questions seeking recommendations for books, tools, software libraries, and more. You can edit the question so it can be answered with facts and citations. Closed 3 years ago. Improve this question Overview One of the things I’ve … Read more
I have the following code. I’m getting error: “The cast to value type ‘Int32’ failed because the materialized value is null. Either the result type’s generic parameter or the query must use a nullable type.” when CreditHistory table has no records. var creditsSum = (from u in context.User join ch in context.CreditHistory on u.ID equals … Read more
var items = from c in contacts select new ListItem { Value = c.ContactId, //Cannot implicitly convert type ‘int’ (ContactId) to ‘string’ (Value). Text = c.Name }; var items = from c in contacts select new ListItem { Value = c.ContactId.ToString(), //Throws exception: ToString is not supported in linq to entities. Text = c.Name }; … Read more
I know some differences of LINQ to Entities and LINQ to Objects which the first implements IQueryable and the second implements IEnumerable and my question scope is within EF 5. My question is what’s the technical difference(s) of those 3 methods? I see that in many situations all of them work. I also see using … Read more
Can someone please explain what a GroupJoin() is? How is it different from a regular Join()? Is it commonly used? Is it only for method syntax? What about query syntax? (A c# code example would be nice) 3 Answers 3
In using the EntityFramework, I get the error “A lambda expression with a statement body cannot be converted to an expression tree” when trying to compile the following code: Obj[] myArray = objects.Select(o => { var someLocalVar = o.someVar; return new Obj() { Var1 = someLocalVar, Var2 = o.var2 }; }).ToArray(); I don’t know what … Read more
In T-SQL you could have a query like: SELECT * FROM Users WHERE User_Rights IN (“Admin”, “User”, “Limited”) How would you replicate that in a LINQ to Entities query? Is it even possible? 9 Answers 9
I have a stored procedure that has three parameters and I’ve been trying to use the following to return the results: context.Database.SqlQuery<myEntityType>(“mySpName”, param1, param2, param3); At first I tried using SqlParameter objects as the params but this didn’t work and threw a SqlException with the following message: Procedure or function ‘mySpName’ expects parameter ‘@param1’, which … Read more
I have a procedure in SQL that I am trying to turn into Linq: SELECT O.Id, O.Name as Organization FROM Organizations O JOIN OrganizationsHierarchy OH ON O.Id=OH.OrganizationsId where OH.Hierarchy like ‘%/12/%’ The line I am most concerned with is: where OH.Hierarchy like ‘%/12/%’ I have a column that stores the hierarchy like /1/3/12/ for example … Read more
Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers. Want to improve this question? Update the question so it’s on-topic for Stack Overflow. Closed 3 years ago. Improve this question How would you rate each of them in terms of: Performance Speed of development Neat, intuitive, maintainable code Flexibility … Read more
