Use .TryAdd to safely add keys to a Dictionary<K, V> CS-R1123

Instead of checking if a key exists using ContainsKey() and then adding an element to a Dictionary<K, V>, consider using the TryAdd() method instead as it is a safer alternative that is easy to read and comprehend.

Bad Practice

if (!dict.Contains(k))
{
    dict.Add(k, v);
}

Recommended

dict.TryAdd(k, v); // Returns a boolean value.