Practical example where Tuple can be used in .Net 4.0?

Question

I have seen the Tuple introduced in .Net 4 but I am not able to imagine where it can be used. We can always make a Custom class or Struct.

Answer 1

Just found the solution of one of my issues in Tuple. It is like declaring a class in scope of a method, but with lazy declaration of its fields names. You operate with collections of tuples, its single instances and then create a collection of anonymous type with the required field names, basing on your tuple. This avoids you from creating the new class for this purpose.

The task is to write a JSON response from LINQ without any additional classes:

 //I select some roles from my ORM my with subrequest and save results to Tuple list
 var rolesWithUsers = (from role in roles
                       select new Tuple(
                         role.RoleName, 
                         role.RoleId, 
                         usersInRoles.Where(ur => ur.RoleId == role.RoleId).Count()
                      ));

 //Then I add some new element required element to this collection
 var tempResult = rolesWithUsers.ToList();
 tempResult.Add(new Tuple(
                        "Empty", 
                         -1,
                         emptyRoleUsers.Count()
                      ));

 //And create a new anonimous class collection, based on my Tuple list
 tempResult.Select(item => new
            {
                GroupName = item.Item1,
                GroupId = item.Item2,
                Count = item.Item3
            });


 //And return it in JSON
 return new JavaScriptSerializer().Serialize(rolesWithUsers);

Of cause we could do this with declaring a new Class for my groups, but the idea to create such an anonimous collections without declaring of new classes.