Conversion inside a lambda expression - LINQ to Entities does not recognize the method 'Int32 ToInt32(System.String)' method

Question

Below is my sample code which gets students details based on DepartmentId.

Public List<CommonDTO> GetStudentsList(int DepId)
{
    List<CommonDTO> studentList = new List<CommonDTO>();

    studentList = SBDB.Students.AsNoTracking()
                      .Where(a => a.DepartmentId == DepId)
                      .Select(s => new CommonDTO()
                                       {
                                           Id = Convert.ToInt32(s.StudentId),
                                           DisplayName = SBDB.Users.Where(m => m.StudentId == s.StudentId).Select(x => x.DisplayName).FirstOrDefault()
                                       })
                      .ToList();

    return studentList;
}

In my database table the StudentId is of type string, where as in my DTO class Id of type Int, the conversion inside the lambda expression is not allowed.

LINQ to Entities does not recognize the method 'Int32 ToInt32(System.String)' method, and this method cannot be translated into a store expression.

Any help on how to fix this ?

If the surtdentId is an integer why are you using convert ToInt32? — jdweng, Aug 10 '19 at 19:03
this has been answered before look at https://stackoverflow.com/questions/13887296/linq-to-entities-does-not-recognize-the-method-int32-int32system-string-meth — Charles Owen, Aug 10 '19 at 19:15
Do an `AsEnumerable` before the `Select` so it will run the `ToInt32` in memory instead of trying to convert it to SQL. — juharr, Aug 10 '19 at 19:19
The DTO type should match the database type. Why is one a string and the other an integer? — jdweng, Aug 10 '19 at 20:43

Conversion inside a lambda expression - LINQ to Entities does not recognize the method 'Int32 ToInt32(System.String)' method

0 Answers0