Introduction:
In this article I will explain how to maintain state of selected checkboxes during paging in gridview using asp.net
Description:
I have one gridview with checkboxes and it contains lot of data for that reason I applied paging for gridview and displaying 8 records per page. After apply the paging in gridview if I select checkboxes in first page and moving to another page and select some checkboxes in second page after that if I come back I am unable to see the previous selected values. At that time I know one new thing that is gridview won’t maintain the state of controls during postback for that reason we need write some code to maintain the previous selected values in gridview. Before seeing the code implemention first Design your aspx page like this
I have one gridview with checkboxes and it contains lot of data for that reason I applied paging for gridview and displaying 8 records per page. After apply the paging in gridview if I select checkboxes in first page and moving to another page and select some checkboxes in second page after that if I come back I am unable to see the previous selected values. At that time I know one new thing that is gridview won’t maintain the state of controls during postback for that reason we need write some code to maintain the previous selected values in gridview. Before seeing the code implemention first Design your aspx page like this
<html xmlns="http://www.w3.org/1999/xhtml"> <head id="Head1" runat="server"> <title>Maintain State Checkboxes during paging</title> </head> <body> <form id="form1" runat="server"> <div> <asp:GridView runat="server" ID="gvdetails" AllowPaging="true" AllowSorting="true"AutoGenerateColumns="false" onpageindexchanging="gvdetails_PageIndexChanging" PageSize="8"DataKeyNames="UserId"> <RowStyle BackColor="#EFF3FB" /> <FooterStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" /> <PagerStyle BackColor="#2461BF" ForeColor="White" HorizontalAlign="Center" /> <HeaderStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" /> <AlternatingRowStyle BackColor="White" /> <Columns> <asp:TemplateField HeaderText="Select"> <ItemTemplate> <asp:CheckBox ID="chkSelect" runat="server" /> </ItemTemplate> </asp:TemplateField> <asp:BoundField DataField="UserId" HeaderText="UserId" /> <asp:BoundField DataField="UserName" HeaderText="UserName" /> <asp:BoundField DataField="LastName" HeaderText="LastName" /> <asp:BoundField DataField="Location" HeaderText="Location" /> </Columns> </asp:GridView> </div> </form> </body> </html> |
After completion of aspx page design add the following references in code behind
using System.Collections; using System.Data; using System.Data.SqlClient; | |
After completion of adding reference write the following code in code behind
protected void Page_Load(object sender, EventArgs e) { if(!IsPostBack) { BindGridData(); } } //This method is used to bind the gridview protected void BindGridData() { SqlConnection con = new SqlConnection("Data Source=SureshDasari;Integrated Security=true;Initial Catalog=MySampleDB"); SqlCommand cmd = new SqlCommand("select * from UserInformation", con); SqlDataAdapter da = new SqlDataAdapter(cmd); DataSet ds = new DataSet(); da.Fill(ds); gvdetails.DataSource = ds; gvdetails.DataBind(); } protected void gvdetails_PageIndexChanging(object sender, GridViewPageEventArgs e) { SaveCheckedValues(); gvdetails.PageIndex = e.NewPageIndex; BindGridData(); PopulateCheckedValues(); } //This method is used to populate the saved checkbox values private void PopulateCheckedValues() { ArrayList userdetails = (ArrayList)Session["CHECKED_ITEMS"]; if (userdetails != null && userdetails.Count > 0) { foreach (GridViewRow gvrow in gvdetails.Rows) { int index = (int)gvdetails.DataKeys[gvrow.RowIndex].Value; if (userdetails.Contains(index)) { CheckBox myCheckBox = (CheckBox)gvrow.FindControl("chkSelect"); myCheckBox.Checked = true; } } } } //This method is used to save the checkedstate of values private void SaveCheckedValues() { ArrayList userdetails = new ArrayList(); int index = -1; foreach (GridViewRow gvrow in gvdetails.Rows) { index = (int)gvdetails.DataKeys[gvrow.RowIndex].Value; bool result = ((CheckBox)gvrow.FindControl("chkSelect")).Checked; // Check in the Session if (Session["CHECKED_ITEMS"] != null) userdetails = (ArrayList)Session["CHECKED_ITEMS"]; if (result) { if (!userdetails.Contains(index)) userdetails.Add(index); } else userdetails.Remove(index); } if (userdetails != null && userdetails.Count > 0) Session["CHECKED_ITEMS"] = userdetails; } |
If you observe above code I written one method to bind our gridview and written two more methods those are SaveCheckedValues and PopulateCheckedValues these two methods are used to maintain the state of selected checkbox values during paging in gridview. In SaveCheckedValues method I used Session variable to maintain the selected checkbox values after that by using this saved session values I am populating the checkbox state in PopulateCheckedValues method.
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