c# - merging two lists<T> and compare -

possible duplicate:
comparing 2 list<>

emp_db_snapshot - loading db fresh copy of user have selected in past:

emp_selected_by_user - user selected list, user may change selected or may add more list of may remove list:

//let have 2 rows in list. list<employee> emp_db_snapshot = new list<employee>(); emp_db_snapshot = employeelistfromdb ; //loads list db  //let have 2 rows in list. list<employee> emp_selected_by_user = new list<employee>(); emp_selected_by_user = myselectedemployee //loads list selected user.   //merging 2 lists: //got total of 4 rows. list<employee> allemployee = emp_db_snapshot.union(emp_selected_by_user).tolist(); 

so question is:

how can differentiate or compare ?

i make attempt answer question.

you make collection of differences between each collection if happen have of same data.

var differenceslist = lista.where(x => !listb.any(x1 => x1.id == x.id)).union(listb.where(x => !lista.any(x1 => x1.id == x.id))); 

you suppose @ point find intersection between collections , merge result list of differences. allow have single collection data appearing once.