要比较两个字符串是否相等，有两种方法：

string toBeTested = "67412";
bool result;

result = toBeTested.Equals("67413");
和
result = toBeTested == "67413";

哪一种方法好呢？

测试程序：
int times = 100000000;
int start, end;
int i;
bool result;
string toBeTested = "67412";

start = System.Environment.TickCount;
for(i=0; i {
result = toBeTested.Equals("67412");
}
end = System.Environment.TickCount;
Console.WriteLine("Equals True Time: " + (end-start)/1000.0 + " Seconds");
start = System.Environment.TickCount;
for(i=0; i {
result = toBeTested == "67412";
}
end = System.Environment.TickCount;
Console.WriteLine("== True Time: " + (end-start)/1000.0 + " Seconds");
start = System.Environment.TickCount;
for(i=0; i {
result = toBeTested.Equals("67413");
}
end = System.Environment.TickCount;

Console.WriteLine("Equals False Time: " + (end-start)/1000.0 + " Seconds");
start = System.Environment.TickCount;
for(i=0; i {
result = toBeTested == "67413";
}
end = System.Environment.TickCount;
Console.WriteLine("== False Time: " + (end-start)/1000.0 + " Seconds");


结果：

Equals True Time: 3.234 Seconds
== True Time: 0.562 Seconds
Equals False Time: 3.391 Seconds
== False Time: 3.891 Seconds

可见当结果为true时，==比Equals()快很多；当结果为false时，Equals()略快于==。
结论：如果要比较的字符串相同的多，就用==；要比较的字符串中不同的多，就用Equals()。