在 C# 中创建一个常量字典 [英] Creating a constant Dictionary in C#

问题描述

创建strings 到ints 的常量(在运行时永远不会改变)映射的最有效方法是什么?

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

我尝试过使用 const 字典 ，但这没有奏效.

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

我可以实现一个不可变的包装器 具有适当的语义，但这似乎仍然不完全正确.

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

对于那些问过的人，我正在实施 IDataErrorInfo 在生成的类中，我正在寻找一种方法来使 columnName 查找到我的描述符数组中.

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(测试时打错了！天啊！)那个 switch 接受字符串，所以这就是我要使用的.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

在 C# 中创建真正的编译时生成的常量字典并不是一项简单的任务.实际上，这里的所有答案都没有真正做到这一点.

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.

虽然有一种解决方案可以满足您的要求，但不一定是好的；请记住，根据 C# 规范，switch-case 表被编译为常量哈希跳转表.也就是说，它们是常量字典，而不是一系列 if-else 语句.所以考虑一个像这样的 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，这很丑陋.

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

这篇关于在 C# 中创建一个常量字典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！