CultureInfo.CurrentCulture与Thread.CurrentThread.CurrentCulture的区别

Question

因此，我做了一些测试，在这些测试中，我需要触发一些线程，并执行一些修改CurrentCulture的日期时间部分，并且想知道CultureInfo.CurrentCulture和Thread.CurrentThread.CurrentCulture之间是否有任何区别。

对于两个intellisense都告诉我：

Gets or sets the culture for the current thread.
Returns:
An object that represents the culture for the current thread.

我的代码：

using System.Globalization;

Console.WriteLine("Hello, World!");
string dateValueString = "05/07/2022";

CultureInfo enGB = new CultureInfo("en-GB");
CultureInfo enUS = new CultureInfo("en-US");

DateTime result = DateTime.Now;
DateTime result2 = DateTime.Now;

Console.WriteLine($"CurrentCulture: {CultureInfo.CurrentCulture.Name} - ThreadCulture: {Thread.CurrentThread.CurrentCulture.Name}");
if (DateTime.TryParse(dateValueString, enGB, DateTimeStyles.None, out result))
{
    Console.WriteLine($"Original: {dateValueString} Parsed: {result}. Day: {result.Day}. Month: {result.Month}. Year: {result.Year}");
    result2 = DateTime.Parse(dateValueString);
    Console.WriteLine($"[Parse]Original: {dateValueString} Parsed: {result2}. Day: {result2.Day}. Month: {result2.Month}. Year: {result2.Year}");
}
Console.WriteLine(System.Environment.NewLine);

Thread.CurrentThread.CurrentCulture = enGB;
Console.WriteLine($"CurrentCulture: {CultureInfo.CurrentCulture.Name} - ThreadCulture: {Thread.CurrentThread.CurrentCulture.Name}");
if (DateTime.TryParse(dateValueString, enGB, DateTimeStyles.None, out result))
{
    Console.WriteLine($"Original: {dateValueString} Parsed: {result}. Day: {result.Day}. Month: {result.Month}. Year: {result.Year}");
    result2 = DateTime.Parse(dateValueString);
    Console.WriteLine($"[Parse]Original: {dateValueString} Parsed: {result2}. Day: {result2.Day}. Month: {result2.Month}. Year: {result2.Year}");
}
Console.WriteLine(System.Environment.NewLine);

Thread.CurrentThread.CurrentCulture = enUS;
Console.WriteLine($"CurrentCulture: {CultureInfo.CurrentCulture.Name} - ThreadCulture: {Thread.CurrentThread.CurrentCulture.Name}");
if (DateTime.TryParse(dateValueString, enGB, DateTimeStyles.None, out result))
{
    Console.WriteLine($"Original: {dateValueString} Parsed: {result}. Day: {result.Day}. Month: {result.Month}. Year: {result.Year}");
    result2 = DateTime.Parse(dateValueString);
    Console.WriteLine($"[Parse]Original: {dateValueString} Parsed: {result2}. Day: {result2.Day}. Month: {result2.Month}. Year: {result2.Year}");
}
Console.WriteLine(System.Environment.NewLine);

new Thread(() =>
{
    Thread.CurrentThread.CurrentCulture = enGB;
    Console.WriteLine($"CurrentCulture: {CultureInfo.CurrentCulture.Name} - ThreadCulture: {Thread.CurrentThread.CurrentCulture.Name}");
    if (DateTime.TryParse(dateValueString, enGB, DateTimeStyles.None, out result))
    {
        Console.WriteLine($"[Thread] Original: {dateValueString} Parsed: {result}. Day: {result.Day}. Month: {result.Month}. Year: {result.Year}");
        result2 = DateTime.Parse(dateValueString);
        Console.WriteLine($"[Thread][Parse]Original: {dateValueString} Parsed: {result2}. Day: {result2.Day}. Month: {result2.Month}. Year: {result2.Year}");

    }
}).Start();
Console.WriteLine(System.Environment.NewLine);

输出：

CurrentCulture: es-ES - ThreadCulture: es-ES
Original: 05/07/2022 Parsed: 05/07/2022 0:00:00. Day: 5. Month: 7. Year: 2022
[Parse]Original: 05/07/2022 Parsed: 05/07/2022 0:00:00. Day: 5. Month: 7. Year: 2022


CurrentCulture: en-GB - ThreadCulture: en-GB
Original: 05/07/2022 Parsed: 05/07/2022 00:00:00. Day: 5. Month: 7. Year: 2022
[Parse]Original: 05/07/2022 Parsed: 05/07/2022 00:00:00. Day: 5. Month: 7. Year: 2022


CurrentCulture: en-US - ThreadCulture: en-US
Original: 05/07/2022 Parsed: 7/5/2022 12:00:00 AM. Day: 5. Month: 7. Year: 2022
[Parse]Original: 05/07/2022 Parsed: 5/7/2022 12:00:00 AM. Day: 7. Month: 5. Year: 2022



CurrentCulture: en-GB - ThreadCulture: en-GB
[Thread] Original: 05/07/2022 Parsed: 05/07/2022 00:00:00. Day: 5. Month: 7. Year: 2022
[Thread][Parse]Original: 05/07/2022 Parsed: 05/07/2022 00:00:00. Day: 5. Month: 7. Year: 2022

Answer 1

CultureInfo.CurrentCulture与Thread.CurrentThread.CurrentCulture的区别

令人惊讶的是，以前没有人问过这个问题。，尽管人们已经开始询问Application.CurrentCulture了。

无论如何：Thread.CurrentThread.CurrentCulture (或特定的Thread.CurrentCulture )的属性getter只返回CultureInfo.CurrentCulture，从源代码中可以看到。

class Thread
{
    // ...

    public CultureInfo CurrentCulture
    {
        get
        {
            RequireCurrentThread();
            return CultureInfo.CurrentCulture;
        }
        set
        {
            if (this != CurrentThread)
            {
                SetCultureOnUnstartedThread(value, uiCulture: false);
                return;
            }
            CultureInfo.CurrentCulture = value;
        }
    }

    // ...
}

因此，就您而言:没有差别，您的测试也是多余的。

如果您想知道，CultureInfo.CurrentCulture是一个简单的属性，它可以读写到字段 (因此真正的逻辑在CLR中，我想是这样的)：

public partial class CultureInfo : IFormatProvider, ICloneable
{
    // ...
   
    [ThreadStatic]
    private static CultureInfo? s_currentThreadCulture;

    [ThreadStatic]
    private static CultureInfo? s_currentThreadUICulture;

    // ...

    public static CultureInfo CurrentCulture
    {
        get
        {
            return s_currentThreadCulture ??
                s_DefaultThreadCurrentCulture ??
                s_userDefaultCulture ??
                InitializeUserDefaultCulture();
        }
        set
        {
            ArgumentNullException.ThrowIfNull(value);

            if (s_asyncLocalCurrentCulture == null)
            {
                Interlocked.CompareExchange(ref s_asyncLocalCurrentCulture, new AsyncLocal<CultureInfo>(AsyncLocalSetCurrentCulture), null);
            }
            s_asyncLocalCurrentCulture!.Value = value;
        }
    }

    // ...
}