未定义或导入预定义类型“ System.ValueTuple´2” [英] Predefined type 'System.ValueTuple´2´ is not defined or imported
问题描述
我已经安装了Visual Studio 15 Preview 3,并尝试使用新的元组功能
I've installed Visual Studio 15 Preview 3 and tried to use the new tuple feature
static void Main(string[] args)
{
var x = DoSomething();
Console.WriteLine(x.x);
}
static (int x, int y) DoSomething()
{
return (1, 2);
}
编译时出现错误:
未定义或导入'System.ValueTuple´2'预定义类型
Predefined type 'System.ValueTuple´2´ is not defined or imported
根据博客帖子,默认情况下此功能应处于启用状态。
According to the blog post, this features should be "on" by default.
我做错了什么?
推荐答案
.NET 4.6 .2或更低版本,.NET Core 1.x和.NET Standard 1.x,您需要安装NuGet软件包 System.ValueTuple
:
For .NET 4.6.2 or lower, .NET Core 1.x, and .NET Standard 1.x you need to install the NuGet package System.ValueTuple
:
Install-Package "System.ValueTuple"
或在VS 2017中使用包引用:
Or using a package reference in VS 2017:
<PackageReference Include="System.ValueTuple" Version="4.4.0" />
.NET Framework 4.7,.NET Core 2.0和.NET Standard 2.0包括这些类型。
.NET Framework 4.7, .NET Core 2.0, and .NET Standard 2.0 include these types.
这篇关于未定义或导入预定义类型“ System.ValueTuple´2”的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!