c# - How to split elements of the group in many lists? -

i have a list (originallist) elements of type mytype. type is:

mytype {     long idreferenceelement;     long idelement;     string value; } 

so separate in lists each group of elements, each group has elements same idreferenceelement.

for example, list of lists, each list of main list has elements of same group.

list<list<mytype>> 

an example, have original list elements:

• item1(1,1,1);
• item2(1,2,2);
• item3(1,3,3);
• item4(2,4,4);
• item5(2,5,5);
• item6(2,6,6);
• item7(3,7,7);
• item8(3,8,8);
• item9(3,9,9);

i 3 lists:

list1 items: - item1(1,1,1); - item2(1,2,2); - item3(1,3,3);

list2: - item4(2,4,4); - item5(2,5,5); - item6(2,6,6);

list3: - item7(3,7,7); - item8(3,8,8); - item9(3,9,9);

to it, trying that:

list<list>> myresultlist = myoriginallist.groupby(x=>x.idreferenceelement).tolist(); 

it not work, because group element not list. know how access each group of grouping , covert list.

thanks much.

list<list<mytype>> myresultlist =        myoriginallist.groupby(x=>x.idreferenceelement)                     .select(gr=>gr.tolist()) // convert each group list                     .tolist();