不用知道长度,可以直接替换。两种办法:
NO.1:
string s="select * from admin where userName=@username and pass=@pass";
s=s.replace("@username","你要替换的用户名");
s=s.replace("@pass","你要替换的密码");
NO.2:
string s="select * from admin where userName={0} and pass={1}";
s=string.Format(s,"你要替换的用户名","你要替换的密码")