Add a list to another list in c#

Question

I have a List A as below

var act= (from a in _db.Activities
                          where a.UserID == userid
                          select new SchoolDetail
                          {
                              SchoolName = a.School,
                              SchoolCode = a.SchoolID
                          }).Distinct().ToList(); 

Then I have another list List B

var sch= (from s in _db.Schools
                           where s.UserID == userid
                           select new SchoolDetail
                           {
                               SchoolName = s.SName,
                               SchoolCode = s.SCode
                           }).Distinct().ToList();  

Now I want to append List B to List A and I tried using AddRange -

var schools = act.AddRange(sch);  

But I am getting an error message on AddRange line -

Exceptions - Argument null exception
Cannot assign void to an implicitly-typed variable

What am I doing wrong and how can I fix it?

Thanks!

Answer 1

Solved it using a Concat instead of AddRange

var schools = act.Concat(sch);