这个 Dictionary 初始值设定项有什么问题

Question

我可能完全失明了，但我看不出这段代码有什么问题：

public static Dictionary<States, string> NameMap = new Dictionary<States, string>
{
    [States.State1] = "State1",
    [States.State2] = "State2",
    [States.State3] = "State3",
    [States.State4] = "State4",
    [States.State5] = "State5",
    [States.State6] = "State6"
};

尝试构建时，我听到了这些错误：

Invalid expression term '['

（这指向每行的第一个括号）

和

Syntax error, ',' expected

这指向 * 列：

[States*.State1]* = "State1",

如有任何帮助，我们将不胜感激。通过 .Add 将这些值放入工作正常。

顺便说一句，States 是一个枚举。

Answer 1

问题是由 Resharper 引起的，只是假设我使用的是 C# 6 编译器并且 'correcting' 我的代码相应。经查，我用的不是C#6，幸亏Resharper我没删

Answer 2

你的语法是正确的！

你可以在这里测试：http://www.volatileread.com/utilitylibrary/snippetcompiler?id=69450

这称为索引初始值设定项

Object and collection initializers are useful for declaratively initializing fields and properties of objects, or giving a collection an initial set of elements. Initializing dictionaries and other objects with indexers is less elegant. We are adding a new syntax to object initializers allowing you to set values to keys through any indexer that the new object has

var numbers = new Dictionary<int, string> {
    [7] = "seven",
    [9] = "nine",
    [13] = "thirteen"
};

来源：https://github.com/dotnet/roslyn/wiki/New-Language-Features-in-C%23-6

这个 Dictionary 初始值设定项有什么问题

What is wrong with this Dictionary initializer

c#

c#-6.0