Default Null Value for Key Not Found in Dictionary?

Is it possible to set a default null value for a case where a key is not found in a dictionary or array?

KeyNotFoundException: The given key was not present in the dictionary.
System.Collections.Generic.Dictionary`2[System.String,System.Int32].get_Item (System.String key)

use Dictionary.TryGetValue

int result = 0;
dict.TryGetValue("Foo", out result);


int result = 0;
if (!dict.TryGetValue("Foo", out result))
    result = 42; // Default value if we can't get it.