在C＃元组中使用Int64

Question

I'm sure this is something simple, but I'm getting a compiler error when using the .Create() method of the new Tuple class.

Dictionary<long, Tuple<long, long>> test = new Dictionary<long, Tuple<long, long>>();
test.Add(1, Tuple.Create(1, 2)); // <-- compiler error

The error is that Tuple.Create has invalid arguments, as it is expecting longs, and the numbers I've put in are being considered as integers.

In this case yes they are within the range of int, but they may may sometimes have a value too big for an int.

I could cast (long)1 to get the code to compile, but this doesn't seem right - what am I missing?

Answer 1

Use the L suffix to specify that you want your numbers to be of type long :

test.Add(1, Tuple.Create(1L, 2L));

Without the suffix, .NET assumes these numbers to be int s and thus creates a Tuple<int, int> instance instead of the desired Tuple<long, long> .

Answer 2

Your code is equivalent:

Tuple<long, long> yourTuple = Tuple.Create(1, 1);

But, because 1 can be either int or long , so by default, compiler will return Tuple<int, int> when calling:

 Tuple.Create(1, 1)  

That is why you get compiler error. Therefore, you need to make casting explicitly by using generic version:

Tuple.Create<long, long>(1, 1);