C# 7 在 VS 15 Preview 4 中工作吗？

Question

我尝试了一个简单的测试，但它不喜欢输出变量

作为一个简单的测试，我写了这个（也许它有一些简单的错误，但我也遇到了模式和元组的问题）

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication2
{

    public class Program
    {
        static void Main(string[] args)
        {
            Runner runner = new ConsoleApplication2.Runner();
            Point p = new ConsoleApplication2.Point();
            runner.PrintCoordinates(p);
        }
    }


    public class Point
    {
        int x = 20;
        int y = 50;
        public void GetCoordinates(out int a, out int b)
        {
            a = x;
            b = y;
        }
    }

    public class Runner
    {
        public void PrintCoordinates(Point p)
        {
            p.GetCoordinates(out int x, out int y);
            Console.WriteLine($"({x}, {y})");       // x does not exist in current context
        }
    }
}

Answer 1

根据this post，其中PrintCoordinates示例方法来自：

Note: In Preview 4, the scope rules are more restrictive: Out variables are scoped to the statement they are declared in. Thus, the above example will not work until a later release.

新的元组也遇到了类似的问题，尽管您似乎可以通过下载 NuGet 部分解决该问题：

Note: Tuples rely on a set of underlying types, that aren’t included in Preview 4. To make the feature work, you can easily get them via NuGet:

Right-click the project in the Solution Explorer and select “Manage NuGet Packages…”

Select the “Browse” tab, check “Include prerelease” and select “nuget.org” as the “Package source”

Search for “System.ValueTuple” and install it.

C# 7 在 VS 15 Preview 4 中工作吗？

Is C# 7 working in VS 15 Preview 4?

c#

c#-7.0