.Net 4.5和4.0中Async方法的Out关键字的替换是什么？

Question

All i want to use Out keyword with my Async function. According to MSDN it is not possible Async modifiers not supports to the out keyword. So is there any alternate in .Net framework 4.5/4.0 ?

Answer 1

You can declare the async function to return Tuple instead. With that the function still able to return multiple values without using out parameter.

public async Task<Tuple<string, int, bool>>SomeFunctionAsync()
{
    return new Tuple<string, int, bool>("foo", 0, false);
}

For Reference :

• Tuple Class
• Why async methods cannot have ref or out parameters?

UPDATE :

you can use shorter syntax as suggested by @svick in comment. Following function return the same value, but using Tuple.Create :

public async Task<Tuple<string, int, bool>>SomeFunctionAsync()
{
    return Tuple.Create("foo", 0, false);
}