c# - 单值数据的 session 正在从数据库获取，而双值数据的 session 未到来

Question

这是我的代码

using (SqlCommand cmd = new SqlCommand("select * from Products where cast(ProductID as nvarchar(100)) in ('" + Session["Products"] + "')", con))
{
     con.Open();
     using (SqlDataReader sdr = cmd.ExecuteReader())
     {
          while (sdr.Read())
          {
               customers.Add(new ProductsData());
               customers[customers.Count - 1].ProductID = Convert.ToInt32(sdr["ProductID"].ToString());
               customers[customers.Count - 1].CategoryID = Convert.ToInt32(sdr["CategoryID"].ToString());
               customers[customers.Count - 1].Title = sdr["Title"].ToString();
               customers[customers.Count - 1].ThumbNail = sdr["ThumbNail"].ToString();
               customers[customers.Count - 1].IsActive = Convert.ToBoolean(sdr["IsActive"].ToString());
               customers[customers.Count - 1].FlashPath = sdr["FlashPath"].ToString();
               customers[customers.Count - 1].Price = Convert.ToDouble(sdr["Price"]);
               customers[customers.Count - 1].Description = sdr["Description"].ToString();
               //customers[customers.Count - 1].CustomerID = Convert.ToInt32(sdr["customer_id"]);
               //customers[customers.Count - 1].FirstName = sdr["firstname"].ToString();
               //customers[customers.Count - 1].LastName = sdr["lastname"].ToString();
          }
      con.Close();
      //return customers;
   }
}

这里当Session["Products"]值为1时，数据来了，正在进入while循环

当 Session["Products"] 值为 1,2 时，循环没有进入我的代码问题是什么 Plz 你能给我建议吗

session 数据声明已更新

 protected void chkFocusArea_CheckedChanged(object sender, EventArgs e)
    {
        CheckBox cb = (CheckBox)sender;
        //update label count if checkbox is checked
        ListViewItem item = (ListViewItem)cb.NamingContainer;
        ListViewDataItem dataItem = (ListViewDataItem)item;

        string code = productslist.DataKeys[dataItem.DisplayIndex].Value.ToString();
        //Header h1 = (Header)Page.LoadControl("~/UserControls/Header.ascx");

        //CitandPrototype.UserControls.Header h1 = new UserControls.Header();
        //Label mylabel = new Label();
        //mylabel=(Label)h1.FindControl("lblitems");


        string mylabel = ((Label)((this.Master).FindControl("Header")).FindControl("lblitems")).Text;

        string mylabelitems = ((HiddenField)((this.Master).FindControl("Header")).FindControl("lblitemshidden")).Value;

        if (!mylabelitems.Contains(code))

            if (mylabel.Length == 0)
        {
           // mylabelitems += "," + code;
            mylabelitems = code;
        }
        else
        {
           // mylabelitems = code;
            mylabelitems += ","+code;
        }

        int.TryParse(mylabel, out x);

        if (cb.Checked)
        {
            x++;
        }
        else
        {
            if (x > 0)
                x -= 1;
            else
                x = 0;

            mylabelitems=mylabelitems.Replace(code, string.Empty);

        }
        ((Label)((this.Master).FindControl("Header")).FindControl("lblitems")).Text =x.ToString();
        ((HiddenField)((this.Master).FindControl("Header")).FindControl("lblitemshidden")).Value = mylabelitems.Trim();
        Session["ProductCount"] = x.ToString();
        Session["Products"] = mylabelitems.ToString();

    }

Answer 1

这是因为:

using (SqlCommand cmd = new SqlCommand("select * from Products where cast(ProductID as nvarchar(100)) in ('" + Session["Products"] + "')", con))

您的最终查询将变为:

select * from Products where cast(ProductID as nvarchar(100)) in ('1,2')

应该是:

select * from Products where cast(ProductID as nvarchar(100)) in ('1','2')

或

select * from Products where ProductID  in (1,2)

试着写成:

using (SqlCommand cmd = new SqlCommand("select * from Products where ProductID  in (" + Session['Products'] + ")", con))

编辑:

 mylabelitems=mylabelitems.Replace(","+code, string.Empty);