使用反射 Invoke 时设置 CultureInfo

发布于 2024-10-28 07:22:49 字数 1208 浏览 2 评论 0原文

我正在开发一个类型转换器，它在目标类型上查找 Parse 方法。发现没有问题并且调用得很好。问题是当将特定的 CultureInfo 传递给 Invoke 方法时，它没有任何效果。

演示代码：

const BindingFlags flags = BindingFlags.Public | BindingFlags.Static;
var parser = typeof(decimal).GetMethod("Parse", flags, null, new[] { typeof(string) }, null);

var result1 = parser.Invoke(null, flags, null, new[] { "123,456" }, CultureInfo.GetCultureInfo("sv-SE"));
var result2 = parser.Invoke(null, flags, null, new[] { "123,456" }, CultureInfo.GetCultureInfo("en-US"));

Console.WriteLine(result1);
Console.WriteLine(result2);

结果（使用瑞典语语言环境）：
123,456
123,456

因此，发生的情况是 Parse 方法正在工作，但我传递给 Invoke 的 CultureInfo 被忽略。瑞典调用应将逗号识别为小数，美国调用应将逗号识别为千位分隔符。

Invoke 的 CultureInfo 参数应该做什么？ MSDN 说

用于管理类型强制的 CultureInfo 实例。如果为 null，则使用当前线程的 CultureInfo。（例如，这对于将表示 1000 的字符串转换为 Double 值是必要的，因为不同的文化对 1000 的表示方式不同。）

这是否与将参数传递给您正在调用的方法而不是操作时的内部转换有关调用期间的 CurrentCulture？在我继续之前，我只是想弄清楚这一点。我可能需要找到包含 CultureInfo 参数的 Parse 方法......此时我将放弃这个想法。

原文

I'm working on a type converter that looks for a Parse method on the target type. It is found without a problem and invokes just fine. The problem is when passing specific CultureInfo to the Invoke method, it has no effect.

Demo code:

const BindingFlags flags = BindingFlags.Public | BindingFlags.Static;
var parser = typeof(decimal).GetMethod("Parse", flags, null, new[] { typeof(string) }, null);

var result1 = parser.Invoke(null, flags, null, new[] { "123,456" }, CultureInfo.GetCultureInfo("sv-SE"));
var result2 = parser.Invoke(null, flags, null, new[] { "123,456" }, CultureInfo.GetCultureInfo("en-US"));

Console.WriteLine(result1);
Console.WriteLine(result2);

Results (using Swedish locale):
123,456
123,456

So what's happening is that the Parse method is working, but the CultureInfo I pass to Invoke is ignored. The Swedish invocation should be recognising the comma as a decimal, and the American invocation should be recognising the comma as a thousands separator.

What is the CultureInfo parameter of Invoke suppose to be doing? MSDN says

An instance of CultureInfo used to govern the coercion of types. If this is null, the CultureInfo for the current thread is used. (This is necessary to convert a String that represents 1000 to a Double value, for example, since 1000 is represented differently by different cultures.)

Does this have to do with internal conversion when passing parameters to the method you're invoking rather than manipulating the CurrentCulture during invocation? I'm just trying to figure this out before I press on here. I may need to find Parse methods that contain a CultureInfo parameter...at which point I will abandon this idea.

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