Question

Consider the following code, where each key has an identical value:

IDictionary<string, string> quarterbackDictionary = new Dictionary<string, string>();
quarterbackDictionary.Add("Manning", "Manning");
quarterbackDictionary.Add("Brady", "Brady");
quarterbackDictionary.Add("Rivers", "Rivers");

My question:

• Can I remove the redundancy, so that I don’t have to repeat each
  string twice, similar to the
  following:

IDictionary<string, string> quarterbackDictionary = new Dictionary<string, string>();
quarterbackDictionary.Add("Manning");
quarterbackDictionary.Add("Brady");
quarterbackDictionary.Add("Rivers");

FYI:

• I’m using a Dictionary because I want to throw on an attempt to insert a duplicate key.
• A HashSet would not throw on an attempt to insert a duplicate key.

Answer 1

Perhaps you could use an extension method

public static class DictionaryExtensions
{
    public static void Add(this Dictionary<string, string> dictionary,  
        string keyAndValue)
    {
        string value;
        if (dictionary.TryGetValue(keyAndValue, out value))
        {
            throw new Exception();
        }

        dictionary.Add(keyAndValue, keyAndValue);
    }
}