組元(Tuple)是C# 4.0引入的一個新特性，可以在.NET Framework 4.0或更高版本中使用。組元使用泛型來簡化類的定義，多用於方法的返回值。在函數需要返回多個類型的時候，就不必使用out , ref等關鍵字了，直接定義一個Tuple類型，使用起來非常方便。
1 //1 member
2 Tuple<int> test = new Tuple<int>(1); 3 //2 member ( 1< n <8)
4 Tuple<int, int> test2 = Tuple.Create<int, int>(1, 2); 5 //8 member, the last member must be tuple type.
6 Tuple<int, int, int, int, int, int, int, Tuple<int>> test3 7 = new Tuple<int, int, int, int, int, int, int, Tuple<int>>(1, 2, 3, 4, 5, 6, 7, new Tuple<int>(8)); 8
9 //output
10 Console.WriteLine(test.Item1); 11 Console.WriteLine(test2.Item1 + ", " + test2.Item2); 12 Console.WriteLine(test3.Item1 + ", " + test3.Item2 + ", " + test3.Item3 + ", " + test3.Item4 13 + ", " + test3.Item5 + ", " + test3.Item6 + ", " + test3.Item7 + ", " + test3.Rest.Item1);
更多嵌套定義的例子
1 //2 member, the second member is the nest type tuple.
2 Tuple<int, Tuple<int>> test4 = new Tuple<int, Tuple<int>>(1, new Tuple<int>(2)); 3 //10 member,the 8th member is the nest type tuple.
4 Tuple<int, int, int, int, int, int, int, Tuple<int, int, int>> test5 5 = new Tuple<int, int, int, int, int, int, int, Tuple<int, int, int>>(1, 2, 3, 4, 5, 6, 7, 6 new Tuple<int, int, int>(8, 9, 10)); 7
8 //output
9 Console.WriteLine(test4.Item1 + ", " + test4.Item2.Item1); 10 Console.WriteLine(test5.Item1 + ", " + test5.Item2 + ", " + test5.Item3 + ", " + test5.Item4 11 + ", " + test5.Item5 + ", " + test5.Item6 + ", " + test5.Item7 + ", "
12 + test5.Rest.Item1 + ", " + test5.Rest.Item2 + ", " + test5.Rest.Item3);