建立在C＃中的常量词典 [英] Creating a constant Dictionary in C#

问题描述

什么是最有效的方式来创建一个恒（永远不会改变在运行时）字符串的S映射到 INT S'

What is the most efficient way to create a constant (never changes at runtime) mapping of strings to ints?

我使用的是<一试href="http://stackoverflow.com/questions/268064/c-how-can-dictionarykv-implement-icollectionkeyvaluepairkv-without-having-addke">const字典，但没有成功。

I've tried using a const Dictionary, but that didn't work out.

我可以实现一个<一个href="http://stackoverflow.com/questions/35002/does-c-have-a-way-of-giving-me-an-immutable-dictionary">immutable包装器适当的语义，但仍然似乎并不完全正确。

I could implement a immutable wrapper with appropriate semantics, but that still doesn't seem totally right.

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对于那些谁问，我在生成的类实现IDataErrorInfo，并正在寻找一种方法，使COLUMNNAME查找到我的描述符的数组。

For those who have asked, I'm implementing IDataErrorInfo in a generated class and am looking for a way to make the columnName lookup into my array of descriptors.

我不知道（错字测试时！D'哦！），该交换机接收字符串，所以这就是我要的使用。谢谢！

I wasn't aware (typo when testing! d'oh!) that switch accepts strings, so that's what I'm gonna use. Thanks!

推荐答案

创建一个真正的编译时产生在C＃中恒字典是不是一个真正的简单的任务。事实上，没有一个答案在这里真正实现了。

Creating a truly compile-time generated constant dictionary in C# is not really a straightforward task. Actually, none of the answers here really achieve that.

有一个解决方案，但它符合你的要求，但不一定是好一个;注意，根据到C＃说明书中，切换情况下的表被编译成常量的散列跳转表。也就是说，它们是恒定的字典，而不是一系列的if-else语句。因此，考虑这样一个的switch-case语句：

There is one solution though which meets your requirements, although not necessarily a nice one; remember that according to the C# specification, switch-case tables are compiled to constant hash jump tables. That is, they are constant dictionaries, not a series of if-else statements. So consider a switch-case statement like this:

switch (myString)
{
   case "cat": return 0;
   case "dog": return 1;
   case "elephant": return 3;
}

这正是你想要的。是的，我知道，这是丑陋的。

This is exactly what you want. And yes, I know, it's ugly.

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