Question

I’ve got a list: User{name, groupname} and I’ve got a function AddGroupMemberstip that takes a list of users and a groupname. I need to split up the users based on their groupname, then feed this into this function.

e.g. I ideally would like to do

var groups = users.<SOME LINQ FUNCTION>(u => u.groupname);

foreach(var group in groups)
{
   AddGroupMembership(users.value, users.key);
}

where users.value would be a IEnumerable<User> and users.key would be the groupname which they all share (for that subgroup).

Please can someone suggest something.

Answer 1

You are looking for GroupBy:

foreach (var g in users.GroupBy(u => u.groupname))
{
    AddGroupMembership(g, g.Key);
}

Each group g is itself an IEnumerable<User>, so there is no .value property access when passing the first parameter to AddGroupMembership.