Arrays, multi-dimensional and jagged...in C# -

c# through asp.net 2.0.

in datatable have 2 columns of ids, attributeid , productattributeid.

i want loop through table , 'group' them in such way productattributeids have 1 or more attributeids associated them.

for example, in pseudo-code i'm doing

for each datarow in mydatatable.rows  insert myarray @ index(productattributeid) - corresponding attributeid  end foreach 

so loop , each time same productattributeid present, attributeid added array corresponding.

obviously won't work arrays need size declared etc.

i've tried multi-dimensional arrays, jagged arrays, arraylists, lists of arraylists no avail, code failing yet know in theory want do.

i would, personally, use dictionary<int, list<int>>:

foreach(var row in data) {     // data...     int attributeid = getattributeid();     int productattributeid = getproductattributeid();      list<int> attributes;     if(!dictionary.trygetvalue(productattributeid, out attributes)     {        attributes = new list<int>();        dictionary[productattributeid] = attributes;     }     attributes.add(attributeid); } 

you can of product attributes attribute:

list<int> attributeids = dictionary[productattributeid];