在 .Net 中为复数形式附加“s"的巧妙方法(语法糖) [英] Clever way to append 's' for plural form in .Net (syntactic sugar)

问题描述

我希望能够输入以下内容:

I want to be able to type something like:

Console.WriteLine("You have {0:life/lives} left.", player.Lives);

代替

Console.WriteLine("You have {0} {1} left.", player.Lives, player.Lives == 1 ? "life" : "lives");

所以对于 player.Lives == 1，输出将是:你还剩 1 条生命.
对于 player.Lives != 1 :你还剩 5 条生命.

so that for player.Lives == 1 the output would be: You have 1 life left.
for player.Lives != 1 : You have 5 lives left.

或

Console.WriteLine("{0:day[s]} till doomsday.", tillDoomsdayTimeSpan);

某些系统内置了该功能.我可以在 C# 中接近该符号吗?

Some systems have that built-in. How close can I get to that notation in C#?

是的，我专门寻找语法糖，而不是确定单数/复数形式的方法.

Yes, I am specifically looking for syntactic sugar, and not a method to determine what singular/plural forms are.

推荐答案

您可以创建一个自定义格式化程序:

You can create a custom formatter that does that:

public class PluralFormatProvider : IFormatProvider, ICustomFormatter {

  public object GetFormat(Type formatType) {
    return this;
  }


  public string Format(string format, object arg, IFormatProvider formatProvider) {
    string[] forms = format.Split(';');
    int value = (int)arg;
    int form = value == 1 ? 0 : 1;
    return value.ToString() + " " + forms[form];
  }

}

Console.WriteLine 方法没有采用自定义格式化程序的重载，因此您必须使用 String.Format:

The Console.WriteLine method has no overload that takes a custom formatter, so you have to use String.Format:

Console.WriteLine(String.Format(
  new PluralFormatProvider(),
  "You have {0:life;lives} left, {1:apple;apples} and {2:eye;eyes}.",
  1, 0, 2)
);

输出:

You have 1 life left, 0 apples and 2 eyes.

注意:这是使格式化程序工作的最低要求，因此它不处理任何其他格式或数据类型.理想情况下，它会检测格式和数据类型，如果字符串中有其他格式或数据类型，则将格式传递给默认格式化程序.

Note: This is the bare minimum to make a formatter work, so it doesn't handle any other formats or data types. Ideally it would detect the format and data type, and pass the formatting on to a default formatter if there is some other formatting or data types in the string.

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