public bool TryFoo(string param, out FooThing foo)
{
    try
    {
        // do whatever
        return true;
    }
    catch
    {
        foo = null;
        return false;
    }
}

var dic = new Dictionary<string, string>() { { "Foo", "Bar" } };

string val = String.Empty;
string key = null;

dic.TryGetValue(key, out val); // oops

private int FindEntry(TKey key)
{
  if (key == null)
  {
    ThrowHelper.ThrowArgumentNullException(ExceptionArgument.key);
   }
   // more stuff
}

catch( Exception ex )
{
  Logger.Log( ex );
  Debug.Assert( false );
  foo = null;
  return false;
}

public bool TryGetValue(T key, out U value)
{
    IList<KeyValue> kvCollection = internalArray[key.GetHashCode() % internalArray.Length];
    for(KeyValue kv in kvCollection)
    {
        if(kv.Key == key)
        {
            value = kv.Value;
            return true;
        }
    }
    value = default(U);
    return false;
}

public U GetValue(T key)
{
    U value;
    if (TryGetValue(key, out value))
    {
        return value;
    }
    throw new KeyNotFoundException(key);
}