Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people, just like you, are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
Solved

How to keep data stored in generic List<T> available during all processes at the same page.

Posted on 2016-08-13
3
103 Views
Last Modified: 2016-08-20
I need to Save selected items in generic List<T> . and keep it until selecting all items needed. Then by pressing the second button "show search results" .
My problem was when I press the second pagination page number, I lose the selected items in previous page "the List<T> is reset".
Could anyone help me please to keep these selected items accumulated to the List<T> until I finish all items I need to select from all available pages.
 
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="myForm_EE.aspx.cs" Inherits="myGoogleLike_webapp.myForm_EE" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:Label ID="lblHead" runat="server" Text=" Enter Your searching test here"></asp:Label>
        <br />
        <asp:TextBox ID="mySearch_TextBox" runat="server"></asp:TextBox>
        <asp:Button ID="search_Button" runat="server" Text="Go" OnClick="search_Button_Click" />
        <br />

        <asp:GridView ID="GridView1" runat="server"  AllowPaging="True" OnPageIndexChanging="GridView1_PageIndexChanging" PageSize="20" AutoGenerateColumns="False" >
            <Columns>
                <asp:TemplateField>
                    <ItemTemplate>
                        <asp:CheckBox ID="CheckBox1" runat="server" AutoPostBack="True"  />
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="Employee ID">
                    <ItemTemplate>
                        <asp:Label ID="lblProductID" runat="server" Text='<%# Bind("ProductID") %>'></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:BoundField DataField="Name" HeaderText="Name" />
                <asp:BoundField DataField="Price" HeaderText="Price" />
            </Columns>
        </asp:GridView>
        <br />
        <asp:Button ID="Button1" runat="server" Text="show search results"  />
    </div>
    </form>
</body>
</html>

Open in new window


using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace myGoogleLike_webapp
{
    public partial class myForm_EE : System.Web.UI.Page
    {
        salesDataContext db = new salesDataContext();
        protected void Page_Load(object sender, EventArgs e)
        {

        }

        protected void search_Button_Click(object sender, EventArgs e)
        {
            BindData();
        }

        protected void GridView1_PageIndexChanging(object sender, GridViewPageEventArgs e)
        {
            GridView1.PageIndex = e.NewPageIndex;
            BindData();
        }
        private void BindData()
        {
            string myString = mySearch_TextBox.Text.Trim();
            
            var myProducts = (from mySection in db.Products
                              where mySection.Name.Contains(myString) 
                              select mySection).ToList();

            if ((myProducts != null) && (myProducts.Count() > 0))
            {
                GridView1.DataSource = myProducts;
                GridView1.DataBind();
            }
        }
    }
}

Open in new window

EE_image1.PNGdataContext-diagram.PNG
0
Comment
Question by:Mohammad Alsolaiman
  • 2
3 Comments
 
LVL 9

Accepted Solution

by:
Paweł earned 500 total points
ID: 41757822
sounds to me like every time you page your'e doing a post-back, loosing everything you've selected you're options are as follows

leverage ajax and store selected items in javascript object between page changes
save the (best, but a pain)

create a viewstate to preserve data between postbacks (good and normal for webforms)

save data to a cookie between postbacks (worst, and most painful)

hope that helps, if i cared i'd go with option one, if this thing just has to work i'd go the view state way

https://msdn.microsoft.com/en-us/library/ms972976.aspx
0
 

Assisted Solution

by:Mohammad Alsolaiman
Mohammad Alsolaiman earned 0 total points
ID: 41763663
thank u Pawel. I had use ViewState. it was very helpful.
namespace myGoogleLike_webapp
{
    // View state example
    public partial class viewStateExample : System.Web.UI.Page
    {
        salesDataContext db = new salesDataContext();
        string mySession = "";
        protected void Page_Load(object sender, EventArgs e)
        {
            mySession = (string)ViewState["mySes"];
            Response.Write((string)ViewState["mySes"]);
        }

        protected void search_Button_Click(object sender, EventArgs e)
        {
            BindData();
        }

        protected void GridView1_PageIndexChanging(object sender, GridViewPageEventArgs e)
        {
            GridView1.PageIndex = e.NewPageIndex;
            BindData();
        }
        private void BindData()
        {
            string myString = mySearch_TextBox.Text.Trim();

            var myProducts = (from mySection in db.Products
                              where mySection.Name.Contains(myString)
                              select mySection).ToList();

            if ((myProducts != null) && (myProducts.Count() > 0))
            {
                GridView1.DataSource = myProducts;
                GridView1.DataBind();
            }
        }

        protected void Button1_Click(object sender, EventArgs e)
        {

        }
        protected void CheckBox1_CheckedChanged(Object sender, EventArgs args)
        {
            foreach (GridViewRow gridViewRow in GridView1.Rows)
            {
                CheckBox chk = (CheckBox)gridViewRow.FindControl("CheckBox1");
                if (chk != null & chk.Checked)
                {
                    string mylblProductID = ((Label)gridViewRow.FindControl("lblProductID")).Text;
                    Boolean isExist = false;
                    if (mySession != null)
                    {
                        isExist = false;
                        string[] words = mySession.Split(' ');
                        foreach (string word in words)
                        {
                            if (words.Contains(mylblProductID))
                            {
                                isExist = true;
                                break;
                            }
                        }
                        chk.Checked = false;
                        if (isExist == false)
                        {
                            mySession += " " + mylblProductID;
                            gridViewRow.BackColor = System.Drawing.Color.Orange;
                        }
                    }
                    else
                    {
                        mySession += " " + mylblProductID;
                        gridViewRow.BackColor = System.Drawing.Color.Orange;
                    }

                }
            }
            ViewState["mySes"] = mySession;
        }
    }
}
0
 

Author Closing Comment

by:Mohammad Alsolaiman
ID: 41763665
Thank u Pawel very much
1

Featured Post

Resolve Critical IT Incidents Fast

If your data, services or processes become compromised, your organization can suffer damage in just minutes and how fast you communicate during a major IT incident is everything. Learn how to immediately identify incidents & best practices to resolve them quickly and effectively.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Computer science students often experience many of the same frustrations when going through their engineering courses. This article presents seven tips I found useful when completing a bachelors and masters degree in computing which I believe may he…
This article aims to explain the working of CircularLogArchiver. This tool was designed to solve the buildup of log file in cases where systems do not support circular logging or where circular logging is not enabled
This video will show you how to get GIT to work in Eclipse.   It will walk you through how to install the EGit plugin in eclipse and how to checkout an existing repository.
With the power of JIRA, there's an unlimited number of ways you can customize it, use it and benefit from it. With that in mind, there's bound to be things that I wasn't able to cover in this course. With this summary we'll look at some places to go…

856 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question