SqlCommand出现错误!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

SqlCommand cmd=new SqlCommand("select count(*) from login where userName='"+userName+"' and userPwd='"+userPwd"'",con);
//"'",con)这行打了红色波浪线总是说应输入;
到底哪里出了问题?

大家快点快点快点~~~~~~~~~~~~~~~~~~~~~

SqlCommand cmd=new SqlCommand("select count(*) from login where userName='"+userName+"' and userPwd='"+userPwd这里缺个加号"'",con);
应该这样写 就不会乱了 先 string str=string.Format("select count(*) from login where userName='{0}' and userPwd='{1}'",userName,userPwd);
然后SqlCommand cmd=new SqlCommand(str,con);