代码asp.net c＃oledb，cookies，if else [英] code asp.net c# oledb, cookies, if else

问题描述

有人可以帮助理解此代码吗？

Can somebody help understand this code?

protected void Page_Load(object sender, EventArgs e)
    {
        Database database = new Database();

        OleDbConnection conn = database.connectDatabase();

        if (Request.Cookies["BesteldeArtikelen"] == null)
        {
            lbl_leeg.Text = "Er zijn nog geen bestelde artikelen";
        }
        else
        {
            HttpCookie best = Request.Cookies["BesteldeArtikelen"];

            int aantal_bestel = best.Values.AllKeys.Length;
            int[] bestelde = new int[aantal_bestel];
            int index = 0;

            foreach (string art_id in best.Values.AllKeys) 
            {
                int aantalbesteld = int.Parse(aantalVoorArtikel(int.Parse(art_id)));

                int artikel_id = int.Parse(art_id); // moet getalletje zijn

                if (aantalbesteld != 0)  
                {
                    bestelde[index] = artikel_id;
                }
                index++;
            }

            OleDbCommand cmd = new OleDbCommand();
            cmd.Connection = conn;
            cmd.CommandText = "SELECT artikel_id, naam, prijs, vegetarische FROM artikel WHERE artikel_id IN (" +
                String.Join(", ", bestelde) + ")";


            try
            {
                conn.Open();

                OleDbDataReader reader = cmd.ExecuteReader();
                GridView1.DataSource = reader;
                GridView1.DataBind();
            }

            catch (Exception error)
            {
                errorMessage.Text = error.ToString();
            }

            finally
            {
                conn.Close();
            }
        }
    }

代码我真的不明白：

public string aantalVoorArtikel(object id)
    {
        int artikel_id = (int)id;

        if (Request.Cookies["BesteldeArtikelen"] != null &&
            Request.Cookies["BesteldeArtikelen"][artikel_id.ToString()] != null)
        {
            return Request.Cookies["BesteldeArtikelen"][artikel_id.ToString()];
        }
        else
        {
            return "0";
        }
    }

推荐答案

从cookie中提取值并构建一个int数组。 （如果cookie值为null，则显示消息）查询数据库时，int数组将用作SQL IN运算符的值。然后将结果集绑定到GridView。

It extracts values from a cookie and builds an int array. (Displays a message if the cookie value is null) The int array is then used as the value for the SQL IN operator when querying the database. The result set is then bound to the GridView.

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