How to add duplicate keys into the Dictionary

Question

I have some lines from text files that i want to add into the Dictionary.I am using Dictionary for the first time.While adding up starting lines it was Ok but suddenly i got err

Answer 1

We can Use a List of Key Value Pair

List> myduplicateLovingDictionary= new List>();
KeyValuePair myItem = new KeyValuePair(dialedno, line);
myduplicateLovingDictionary.Add(myItem);