Linq for nested loop

Question

I have a loop as follows:

foreach(x in myColl) 
{
    foreach(var y in x.MyList) 
    {
        result.Add(x.MyKey + y)
    }
}

That means within my inner loop I need access to a property of the current outer element.

I´m looking for a LINQ-statement but I´m unsure on it. I tried it by using

result = myColl
    .SelectMany(x => x.MyList)
    .SelectMany(x => /* how to get the key of the outer loop here */ + x)

Answer 1

This is easy with query expressions:

(from x in myColl
 from y in x.MyList
 select x.MyKey + y).ToList()

This works because this translates to:

myColl
.SelectMany(x => x.MyList.Select(item => new { List = x, Item = item }))
.Select(x => ...) //rest of the query, whatever you like

The key is to keep both the list as well as the list items. Channel them through the query using an anonymous type (or any other container).