c# - 如何将 DateTimeFormatInfo.CurrentInfo 和 NumberFormatInfo.CurrentInfo 设置为不变？

Question

我正在重构一些单元测试，发现一些解析策略依赖于 DateTime.TryParseExact 和 sbyte.TryPase，它们本身依赖于 NumberFormatInfo.CurrentInfo 和 DateTimeFormatInfo.CurrentInfo。

为了正确安排我的单元测试，我决定将 NumberFormatInfo 和 DateTimeFormatInfo 的 CurrentInfo 属性设置为它们不变的风格通过:

CultureInfo.CurrentCulture = CultureInfo.InvariantCulture;

然而，出于好奇，我试图检查相应的 InvariantInfo 是否通过单元测试设置，结果证明没有，它们不是。我想知道在这两个 CurrentInfo

中强制执行 InvariantCulture 我缺少什么

[Fact]
public void ShouldReturnInvariantInfo()
{
    CultureInfo.CurrentCulture.NumberFormat = NumberFormatInfo.InvariantInfo;
    CultureInfo.CurrentCulture.DateTimeFormat = DateTimeFormatInfo.InvariantInfo;
    NumberFormatInfo.CurrentInfo.Should().Be(NumberFormatInfo.InvariantInfo);
    DateTimeFormatInfo.CurrentInfo.Should().Be(DateTimeFormatInfo.InvariantInfo);
}

了解底层实现:

NumberFormatInfo.InvariantInfo:

public static NumberFormatInfo CurrentInfo
{
  get
  {
    CultureInfo currentCulture = CultureInfo.CurrentCulture;
    if (!currentCulture._isInherited)
    {
      NumberFormatInfo numInfo = currentCulture.numInfo;
      if (numInfo != null)
        return numInfo;
    }
    return (NumberFormatInfo) currentCulture.GetFormat(typeof (NumberFormatInfo));
  }
}

DateTimeFormatInfo.CurrentInfo:

public static DateTimeFormatInfo CurrentInfo
{
  get
  {
    CultureInfo currentCulture = CultureInfo.CurrentCulture;
    if (!currentCulture._isInherited)
    {
      DateTimeFormatInfo dateTimeInfo = currentCulture.dateTimeInfo;
      if (dateTimeInfo != null)
        return dateTimeInfo;
    }
    return (DateTimeFormatInfo) currentCulture.GetFormat(typeof (DateTimeFormatInfo));
  }
}

Answer 1

如果我理解正确，您想在 Current 文化下运行一些代码(测试)，NumberFormat 和 DateTimeFormat 除外这是不变的。如果是您的情况，我建议克隆当前文化并修改克隆:

// Current culture clone
CultureInfo testCulture = CultureInfo.CurrentCulture.Clone() as CultureInfo;

// modified: current culture except Number and DateTime which are Invariant
testCulture.NumberFormat = CultureInfo.InvariantCulture.NumberFormat;
testCulture.DateTimeFormat = CultureInfo.InvariantCulture.DateTimeFormat;

// and, finally, set back as current
CultureInfo.CurrentCulture = testCulture;

让我们来看看格式

Console.Write(ReferenceEquals(CultureInfo.CurrentCulture.DateTimeFormat,
                              CultureInfo.InvariantCulture.DateTimeFormat) 
     ? "Equals" 
     : "Not Equals");

结果:

Equals

编辑:为了使用修改后的文化运行代码，我们可以为它实现一个类:

  public class TestCulture : IDisposable {
    private CultureInfo m_SavedCulture; 
    private CultureInfo m_TestCulture;
    private bool m_IsDisposed;

    public TestCulture() {
      m_SavedCulture = CultureInfo.CurrentCulture; 

      m_TestCulture = CultureInfo.CurrentCulture.Clone() as CultureInfo;
      m_TestCulture.NumberFormat = CultureInfo.InvariantCulture.NumberFormat;
      m_TestCulture.DateTimeFormat = CultureInfo.InvariantCulture.DateTimeFormat;

      CultureInfo.CurrentCulture = m_TestCulture;
    }

    protected vitrual void Dispose(bool disposing) {
      if (disposing) {
        if (!m_IsDisposed && ReferenceEquals(CultureInfo.CurrentCulture, m_TestCulture)) {
          CultureInfo.CurrentCulture = m_SavedCulture;

          m_IsDisposed = true;
        }
      }
    }

    public void Dispose() => Dispose(true);
  }

然后按如下方式使用它:

  using (new TestCulture()) {
    // Tests which should be run under the specific culture
  }