1  public string Admin(string Name,string Pwd)
 2     {
 3         Admin admin = new Admin();
 4         admin.Name = Name;
 5         admin.Pwd = Pwd;
 6         string CheckAdmin = "select qx from admin where Name=‘" +Name + "‘and Pwd=‘" + Pwd + "‘";
 7         string returndate="";
 8         SqlConnection conn = new SqlConnection("Server=(local);database=vote;uid=sa;pwd=123456;");
 9         try
10         {
11             conn.Open();
12             SqlCommand cmd = new SqlCommand(CheckAdmin, conn);
13             if (cmd.ExecuteScalar() is DBNull)
14             {
15                 return returndate = "用户名存在";
16             }
17             else
18 
19                 return returndate = "用户名不存在";
20 
21         }
22         catch (SqlException ee)
23         {
24 
25             return ee.Message.ToString();
26         }
27 
28     
29     
30     
31     }