Maximizing the DataPager control

The ListView control comes along with the DataPager control. In this example below, I tried to make this pager, work like the pager in ASP.net forum threads. Here’s how my example-page looks like.

By default this pager works only with ListView, although we can alter the databound controls like Repeater, Gridview to make the DataPager work with them. That’s a different story though. Anyway, ListView is a super hybrid of Repeater, DataList, GridView control. Anything which those individual controls can do, ListView can do equally good. So this combination of ListView & Datapager along with UpdatePanel can help in many situations. The DataPager is not very efficient, since it retreives all rows of the underlying DataSource, hence paging with huge data , can run into performance issues. Anyway, here’s the complete code sample.

<%@ Page Title="" Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true" CodeFile="DataPager4.aspx.cs" Inherits="DataPager4" %>

<asp:Content ID="Content1" ContentPlaceHolderID="HeadContent" Runat="Server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" Runat="Server">
<b>Show <asp:DropDownList ID="DropDownList1" AutoPostBack="true" runat="server" AppendDataBoundItems="true" onselectedindexchanged="DropDownList1_SelectedIndexChanged"></asp:DropDownList> records per page</b>
<br /><br />
<asp:ListView ID="ListView1"  runat="server" >
<LayoutTemplate>
<table>
<tr>
<td><b>CustomerID </b></td>
<td><b>CompanyName</b></td>
<td><b>ContactName</b></td>
<td><b>ContactTitle</b></td>
<td><b>City</b></td>
</tr>
<tr id="itemPlaceholder" runat="server"></tr>
</table>
</LayoutTemplate>
<ItemTemplate>
<tr>
<td><%# DataBinder.Eval(Container.DataItem, "CustomerID")%></td>
<td><%# DataBinder.Eval(Container.DataItem, "CompanyName")%></td>
<td><%# DataBinder.Eval(Container.DataItem, "ContactName")%></td>
<td><%# DataBinder.Eval(Container.DataItem, "ContactTitle")%></td>
<td><%# DataBinder.Eval(Container.DataItem, "City")%></td>
</tr>
</ItemTemplate>
</asp:ListView>

<br />
<hr />
<asp:DataPager ID="dp1" runat="server" PagedControlID="ListView1" >
<fields>
<asp:TemplatePagerField>
<PagerTemplate>
<b>Currently on
<asp:Label runat="server" ID="l1" Text="" />
of
<asp:Label runat="server" ID="l2" Text="" />
&nbsp;&nbsp;&nbsp;
</b>
</PagerTemplate>
</asp:TemplatePagerField>

<asp:NextPreviousPagerField ButtonType="Link"  FirstPageText="First |" ShowFirstPageButton="True" ShowNextPageButton="False" ShowPreviousPageButton="False" />
<asp:NextPreviousPagerField ButtonType="Link" LastPageText="Last  " ShowLastPageButton="True" ShowNextPageButton="False" ShowPreviousPageButton="False"  />

<asp:TemplatePagerField>
<PagerTemplate>
&nbsp;&nbsp;
</PagerTemplate>
</asp:TemplatePagerField>

<asp:NextPreviousPagerField ButtonType="Link" NextPageText="Next |" ShowFirstPageButton="False" ShowNextPageButton="True" ShowPreviousPageButton="False" />
<asp:NextPreviousPagerField ButtonType="Link" PreviousPageText="Previous" ShowFirstPageButton="False" ShowNextPageButton="False" ShowPreviousPageButton="True" />

<asp:TemplatePagerField>
<PagerTemplate>
&nbsp;&nbsp;
</PagerTemplate>
</asp:TemplatePagerField>
<asp:NumericPagerField RenderNonBreakingSpacesBetweenControls="true"   CurrentPageLabelCssClass="PageItem" NumericButtonCssClass="PageItem" NextPreviousButtonCssClass="PageItem" />
</fields>
</asp:DataPager>
<hr />
</asp:Content>

 

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

public partial class DataPager4 : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            int _TotalRows = BindListView();
            for (int i = 5; i < _TotalRows; i++)
            {
                ListItem li = new ListItem(i.ToString(), i.ToString());
                DropDownList1.Items.Add(li);
                i = i + 9;
            }
            dp1.PageSize = 5;
        }
    }

    protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
    {
        dp1.PageSize = int.Parse(DropDownList1.SelectedValue);
        dp1.SetPageProperties(0, int.Parse(DropDownList1.SelectedValue), true);
        dp1.DataBind();
    }

    private int BindListView()
    {
        DataTable dt = DataLayer.GetMyData();
        ListView1.DataSource = dt;
        ListView1.DataBind();
        return dt.Rows.Count;
    }

    protected override void OnPreRender(EventArgs e)
    {
        base.OnPreRender(e);
        int _TotalRows = BindListView();

        Label l1 = (Label)(dp1.Controls[0].Controls[1]);
        Label l2 = (Label)(dp1.Controls[0].Controls[3]);
        if (dp1.StartRowIndex > 0)
        {
            l1.Text = (Math.Ceiling((decimal)dp1.StartRowIndex / dp1.PageSize) + 1).ToString();
        }
        else
        {
            l1.Text = "1";
        }
        l2.Text = dp1.TotalRowCount.ToString();
    }
    
}

Hope this helps. Thanks for reading.