How to resolve Cannot convert lambda expression to type 'string' because it is not a delegate type. Error.?

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Hello,

I am using this code in mvc for delete.

C#

public ActionResult Delete()
        {
            string StudentId = Request.QueryString["stuId"].ToString();
            Book_DBEntities objentity = new Book_DBEntities();
            studentdetail objstudentdetail = new studentdetail();
            objstudentdetail = (from data in objentity.studentdetails
                                where data.studentid = StudentId 
                                select data).FirstOrDefault();
            StudentList _objstudentlist = new StudentList();
            _objstudentlist.Id = StudentId;
            _objstudentlist.Name = objstudentdetail.Name;
            _objstudentlist.Address = objstudentdetail.Address;
            _objstudentlist.Marks = (int)objstudentdetail.Marks;
            _objstudentlist.Section = objstudentdetail.Section;
            StudentListModel objstudentlistmodel = new StudentListModel();
            objstudentlistmodel.StudentListDetail = _objstudentlist;
            return View(objstudentlistmodel);
            
        }

but it's showing error in
where data.studentid = StudentId
this line.

Error: Delegate 'System.Func<studentinformation.studentdetail,int,bool>' does not take 1 arguments.

Cannot convert lambda expression to type 'string' because it is not a delegate type.

Cannot implicit convert type 'string' to bool.

These three errors are giving.

How i resolve this error?
Please help me.

Thanks in Advance.

Ankit Agarwal
Software Engineer

Posted 9-Nov-14 22:34pm

ankit.agg1984

Updated 9-Nov-14 22:41pm

Garth J Lancaster

v2

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3 solutions

Solution 3

The above error mentioned:-

Quote:
Cannot convert lambda expression to type 'string' because it is not a delegate type

This error comes sometimes when you have missed the namespace for linq
using System.Linq; or using System.Data.Entity;
Mehdi and Griff are absolutely correct that you have missed out double equals, please just keep in mind and check for the namespaces also. Sometimes the double equals also throws the first error you have mentioned because of the namespaces.
Hope this helps anyway.
Thanks.
:)

Posted 9-Nov-14 23:06pm

Suraj Sahoo | Coding Passion

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Mehdi Gholam · Accepted Answer · 2014-11-09T22:37:00

Solution 1

Try a double == :

C#

objstudentdetail = (from data in objentity.studentdetails
where data.studentid == StudentId
select data).FirstOrDefault();

Posted 9-Nov-14 22:37pm

Mehdi Gholam

Comments

[no name] 10-Nov-14 4:39am

Thanks, I have missed the double ==.

Maciej Los 10-Nov-14 4:44am

+5

Mehdi Gholam 10-Nov-14 5:38am

:)

OriginalGriff · Accepted Answer · 2014-11-09T22:38:00

Solution 2

Um.
Try "==" instead of "="?

C#

where data.studentid = StudentId

Becomes

C#

where data.studentid == StudentId

Posted 9-Nov-14 22:38pm

OriginalGriff

Comments

Garth J Lancaster 10-Nov-14 4:42am

and here I was tidying up the question and you both jump in and answer it - sheesh :-)