Creating SortedDictionary with LinkedList value

Question

I have a class called "OrderItem" and a list of the class's instances. Now I want to create a SortedDictionary that the key would be one of the class properties and value of LinkedList that all of the items in the LinkedList will have the same key property. I want to write a code same as this:

SortedDictionary<Double, LinkedList<OrderItem>> UnitPriceIndex;
foreach (OrderItem item in Data) // Data = list with all the instances of " OrderItem "
{ 
    UnitPriceIndex.Add(item.UnitPrice, LinkedList.add(item) // all items in the list will have the same UnitPrice
}

How can I do it?

Answer 1

You need to make sure the key exists first. If it doesn't, then create it and assign a new list as value.

Then you can just add the current item to the LinkedList. For example:

var UnitPriceIndex = new SortedDictionary<double, LinkedList<OrderItem>>();

foreach (OrderItem item in Data)
{
    // Make sure the key exists. If it doesn't, add it 
    // along with a new LinkedList<OrderItem> as the value
    if (!UnitPriceIndex.ContainsKey(item.UnitPrice))
    {
        UnitPriceIndex.Add(item.UnitPrice, new LinkedList<OrderItem>());
    }

    UnitPriceIndex[item.UnitPrice].AddLast(item);
}