测试在长度为 403 的字符串中查找，特意匹配最后几个字符：
string a = "";
for (int i = 0; i < 100; i++) { a += "aBcD"; }
a += "xYz";
string b = "xyz"; // 特意匹配最后几个字符
Stopwatch sw1 = Stopwatch.StartNew();
bool? r1 = null;
for (int i = 0; i < 10000; i++) { r1 = a.IndexOf(b) >= 0; }
sw1.Stop();
Stopwatch sw2 = Stopwatch.StartNew();
bool? r2 = null;
for (int i = 0; i < 10000; i++) { r2 = a.Contains(b); }
sw2.Stop();
Stopwatch sw3 = Stopwatch.StartNew();
bool? r3 = null;
for (int i = 0; i < 10000; i++) { r3 = a.ToUpper().Contains(b.ToUpper()); }
sw3.Stop();
Stopwatch sw4 = Stopwatch.StartNew();
bool? r4 = null;
for (int i = 0; i < 10000; i++) { r4 = a.ToLower().Contains(b.ToLower()); }
sw4.Stop();
Stopwatch sw5 = Stopwatch.StartNew();
bool? r5 = null;
for (int i = 0; i < 10000; i++) { r5 = a.Contains(b, StringComparison.OrdinalIgnoreCase); }
sw5.Stop();
Stopwatch sw6 = Stopwatch.StartNew();
bool? r6 = null;
for (int i = 0; i < 10000; i++) { r6 = a.Contains(b, StringComparison.CurrentCultureIgnoreCase); }
sw6.Stop();
Stopwatch sw7 = Stopwatch.StartNew();
bool? r7 = null;
for (int i = 0; i < 10000; i++) { r7 = Regex.IsMatch(a, b); }
sw7.Stop();
Stopwatch sw8 = Stopwatch.StartNew();
bool? r8 = null;
for (int i = 0; i < 10000; i++) { r8 = Regex.IsMatch(a, b, RegexOptions.IgnoreCase); }
sw8.Stop();
return Json(new
{
IndexOf_________________ = sw1.Elapsed + " " + r1,
Contains________________ = sw2.Elapsed + " " + r2,
ToUpper_________________ = sw3.Elapsed + " " + r3,
ToLower_________________ = sw4.Elapsed + " " + r4,
OrdinalIgnoreCase_______ = sw5.Elapsed + " " + r5,
CurrentCultureIgnoreCase = sw6.Elapsed + " " + r6,
IsMatch_________________ = sw7.Elapsed + " " + r7,
IsMatchIgnoreCase_______ = sw8.Elapsed + " " + r8,
});结果参考：
{
"indexOf_________________": "00:00:00.1455812 False",
"contains________________": "00:00:00.0003791 False",
"toUpper_________________": "00:00:00.0038182 True",
"toLower_________________": "00:00:00.0026113 True",
"ordinalIgnoreCase_______": "00:00:00.0096550 True",
"currentCultureIgnoreCase": "00:00:00.1596517 True",
"isMatch_________________": "00:00:00.0053627 False",
"isMatchIgnoreCase_______": "00:00:00.0084132 True"
}