经典HSRP实验(CCNP案例)

ToUpperInvariant使用不依赖于区域性进行转换，而ToUpper则使用了当前线程的CultureInfo，进行转换，所以性能会有所影响，以下为测试：

[Test]
public void TestInvariant()
{
Int32 count = 1000 * 1000;
Stopwatch watch = new Stopwatch();

String str = "abcdefghijklmnopqrstuvwxyz中华人民共和国";
watch = Stopwatch.StartNew();
for (int i = 0; i < count; i++)
{
str.ToUpperInvariant();
}
Console.WriteLine("ToUpperInvariant:{0}", watch.Elapsed.ToString());
}

[Test]
public void TestNoInvariant()
{
Int32 count = 1000 * 1000;
Stopwatch watch = new Stopwatch();

String str = "abcdefghijklmnopqrstuvwxyz中华人民共和国";
watch = Stopwatch.StartNew();
for (int i = 0; i < count; i++)
{
str.ToUpper();
}
Console.WriteLine("ToUpper:{0}", watch.Elapsed.ToString());
}

结果：

ToUpperInvariant:00:00:00.2980660

ToUpper:00:00:00.3281423

如果 确认当前的比较和区域性无关的话，推荐使用ToUppperInvariant

ToUpperInvariant