用户登录界面已做好，想根据数据库a里的user表里的username和password来判断登录是否合法，合法就做下一步，请问这个判断怎么写？

Question

用户登录界面已做好，想根据数据库a里的user表里的username和password来判断登录是否合法，合法就做下一步，请问这个判断怎么写？

Answer 1

SqlConnection sqlconn = 。;
                
                SqlCommand sqlcomm = new SqlCommand("select id from admin where
username='"+username+"' and userpwd='"+userpwd+"'", sqlconn);
                
                sqlconn.Open();
                
                try
                {
                    
                    int uid = (Convert.ToInt64)(sqlcomm.ExecuteScalar());                    if (uid > 0)
                    {
                        Session["username"] = uname;
                        Session["uid"] = uid;
                       Response.Redirect("Welcome.aspx");
                    }
                    else
                    {
                        Response.Write("<script language='javascript'>alert('您的用户名或密码错误！');</script>");
                    }                }
                catch
                {                }
                finally
                {
                    sqlconn.Close();
                }

Answer 2

其他都挺好,就是Convert.ToInt64有点问题,改成32也不行

Answer 3

Convert.ToInt32有问题？？不知道是错在哪？？请楼主说清楚点~！

Answer 4

OleDbConnection cnn = new OleDbConnection("PROVIDER=Microsoft.Jet.OLEDB.4.0;DATA Source=E:\\基于窗体的身份验证\\database.mdb");
        if (cnn.State == ConnectionState.Closed)
        {
            cnn.Open();
        }
        OleDbCommand cmd = new OleDbCommand();
        string str = "Select Count(*) from people where user_name='" + username.Text + "'and user_password='" + Password.Text + "'";
        cmd.CommandType = CommandType.Text;
        cmd.CommandText = str;
        cmd.Connection = cnn;
        OleDbDataReader reader = cmd.ExecuteReader();
        while (reader.Read())
        {
            if (reader.GetValue(0).ToString() != "1")
            {
                msg.Text = "Invalid username and password";
            }
            else
            {
                
                Response.Redirect("tt.aspx");
            }
        }

Answer 5

int uid = (Convert.ToInt32)(sqlcomm.ExecuteScalar());
'System.Convert.ToInt32(object)' is a 'method' but is used like a 'type'

Answer 6

liubinstud(百里透红)  你在哪啊?

Answer 7

(Convert.ToInt32)(sqlcomm.ExecuteScalar());
括弧去掉Convert.ToInt32(sqlcomm.ExecuteScalar());