I have found many linq posts on here that group an object by a field but i haven't found a way to group an object by numerous fields.
Lets say i have an object like the following:
class Obj
{
public string field1 {get;set;}
public string field2 {get;set;}
public string field3 {get;set;}
}
Then i have a list of objects like:
List<Obj> ol = new List<Obj>
Obj obj = new Obj();
obj.field1 = "a1";
obj.field2 = "a2";
obj.field3 = "a3";
ol.Add(obj);
obj.field1 = "a4";
obj.field2 = "a5";
obj.field3 = "a6";
ol.Add(obj);
obj.field1 = "a7";
obj.field2 = "a8";
obj.field3 = "a9";
ol.Add(obj);
obj.field1 = "a1";
obj.field2 = "a2";
obj.field3 = "a3";
ol.Add(obj);
So now there is a list of four objects. What i want is to group the list by all three fields. I know how to group the list by 1 field but i have not had any luck when grouping by multiple fields. So the result i am looking for is a list of three since fields 1,2, and 3 are the same in two of the objects.
To group by one field i have done the following which works fine:
var grouped = obj.GroupBy(u => u.field1);
What i am looking for is something like the following which is invalid syntax but it's one of the things i have tried:
var grouped = obj.GroupBy(u => u.field1 && v => v.field2 && w => w.field3);
The idea would be the same thing in sql if you were grouping by multiple fields like:
select * from foo group by field1, field2, field3
Thanks in advance for any help
