How to update a particular field of a particular object in Generic list in c#.net using LINQ

Question

I am creating a Generic List of objects of Employee class.

List<Employee> EmployeeList = new List<Employee>
{
new Employee { ecode=1, ename="Rohit", salary=20000, mgrid="3" },
new Employee { ecode=2, ename="Sangeeta", salary=12000, mgrid="5"},
new Employee { ecode=3, ename="Sanjay", salary=10000, mgrid="5"},
new Employee { ecode=4, ename="Arun", salary=25000, mgrid="3"},
new Employee { ecode=5, ename="Zaheer", salary=30000, mgrid=null}  
};

'mgrid' is the Employee ID of the Manager. I want just increment the salary of the Managers. I tried doing it using the following approach, but salaries of all the employees are getting incremented.

var mgrsal =  from e1 in emplst
              join e2 in emplst
              on e1.ecode.ToString() equals e2.mgrid into empdata
              select new Employee
              {
                  ecode = e1.ecode,
                  ename=e1.ename,
                  salary=e1.salary*1.1,
                  mgrid = e1.mgrid
              };

I am coding in C#.net in Visual Studio IDE and I also tried to use Contains() and Any() methods, but I am unable to use.

Answer 1

LINQ is all about querying, not updating. You can use LINQ to get all managers from the list,

var managers = from e in emplst
               where emplst.Any(x => x.mgrid == e.ecode.ToString())
               select e;

or using JOIN (it would require implementing Equals and GetHashCode methods on Employee class to make Distinct work:

var managers = (from e in emplst
               join e2 in emplst on e.ecode.ToString() equals e2.mgrid
               select e).Distinct();

and then iterate over and change the salary:

foreach(var manager in managers)
    manager.salary *= 1.1;