数据库的连接

 public string Admin(string Name,string Pwd)
    {
        Admin admin = new Admin();
        admin.Name = Name;
        admin.Pwd = Pwd;
        string CheckAdmin = "select qx from admin where Name='" +Name + "'and Pwd='" + Pwd + "'";
        string returndate="";
        SqlConnection conn = new SqlConnection("Server=(local);database=vote;uid=sa;pwd=123456;");
        try
        {
            conn.Open();
            SqlCommand cmd = new SqlCommand(CheckAdmin, conn);
            if (cmd.ExecuteScalar() is DBNull)
            {
                return returndate = "用户名存在";
            }
            else

                return returndate = "用户名不存在";

        }
        catch (SqlException ee)
        {

            return ee.Message.ToString();
        }

    
    
    
    }