Custom Page Items

In some scenarios we need to page the data source but not using a standard partition. For example, in a page with a list of customers, we may be interested to have a pager that contains all the letters, and when a letter is clicked, the customers whose name starts with that letter are shown.

The PagerDataSource has support for that scenario. In order to provide custom page items instead of the usual numbers, we have to set the UseCustomPageItems property to true and we also have to supply the custom page items using the CustomPageItems collection.

One implication of this mode is that each page of data can have any number of items and it is not limited by the PageSize. If we are using a DataSourceControl to supply the data to the PagerDataSource, it has to support paging and the startRowIndexParameter will contain the page item clicked (the maximumRowsParameter is not used in this case). If we are not using a DataSourceControl to supply the data to the PagerDataSource we can supply the data in the PageChanged event as the example Paging a DataSource (2) shows.

In this sample what we are going to use ficticious data showing IP addresses, access time and data downloaded. What we want is to populate the GridView with that data ( obtained from an ObjectDataSource) and let the user to see the data grouped by country. The PagerDataSource is used for this. In this sample, the custom page items are created in code, but they can be created also using the design-time editor.

The source code for this page is shown after the live sample.

IP addresses list

Id	IPAddress	ConnectionTime	KB downloaded	Country
20	201.164.9.7	3/15/2010 3:55:36 AM	755	US
22	111.121.163.94	3/16/2010 10:36:36 PM	296	US
30	174.96.93.39	3/16/2010 12:16:36 AM	47	US
35	92.116.25.236	3/17/2010 12:09:36 AM	217	US
46	181.138.144.21	3/16/2010 1:56:36 AM	676	US
79	55.19.156.95	3/16/2010 11:43:36 PM	761	US
89	142.8.146.252	3/14/2010 6:16:36 PM	257	US
91	51.213.112.37	3/16/2010 10:12:36 AM	657	US
93	57.37.110.193	3/16/2010 3:19:36 PM	766	US
97	1.112.1.15	3/15/2010 10:47:36 AM	83	US
98	13.191.198.184	3/16/2010 10:28:36 PM	289	US

Sample source code

The ASPX file for this sample is:.

                    <%@
                    Page Language="C#" MasterPageFile="~/DefaultMaster.master" AutoEventWireup="true" CodeFile="CustomPageItems.aspx.cs" Inherits="CustomPageItems" Title="Custom Page Items" %>

                    <%@
                    Register Assembly="PagerDataSource" Namespace="Manu.Web.UI.WebControls" TagPrefix="manu" %>

                    <asp:Content 
                            ID="Content1" ContentPlaceHolderID="Content" Runat="Server">

                        <h2>IP addresses list</h2>

                        <manu:PagerDataSource
                    ID="PagerDataSource1"
                    runat="server"
                
                            DataSourceID="ObjectDataSource1"
                    UseCustomPageItems="True">

                        </manu:PagerDataSource>

                        <asp:GridView 
                            ID="GridView1" runat="server" AutoGenerateColumns="False" 
                                        
                                                BackColor="#335789"

                            BorderColor="#133769"
                    BorderStyle="Solid"
                    BorderWidth="1px"
                    
                    DataKeyNames="Id"

                            DataSourceID="PagerDataSource1"
                    CssClass="gridview"
                    AllowSorting="True">

                            <Columns>

                                <asp:BoundField
                    DataField="Id"
                    HeaderText="Id"
                    ReadOnly="True"
                    
                                    SortExpression="Id"
                    />

                                <asp:BoundField
                    DataField="IPAddress"
                    HeaderText="IPAddress" 

                                    SortExpression="IPAddress"
                    />

                                <asp:BoundField
                    DataField="ConnectionTime"
                    HeaderText="ConnectionTime"
                    
                                    SortExpression="ConnectionTime"
                    />

                                <asp:BoundField
                    DataField="KB downloaded"
                    HeaderText="KB downloaded"
                    
                                    SortExpression="KB
                            downloaded" />

                                <asp:BoundField
                    DataField="Country"
                    HeaderText="Country" 

                                    SortExpression="Country"
                    />

                            </Columns>

                            <RowStyle
                    BackColor="White"

                                ForeColor="#436799" />

                            <HeaderStyle
                    ForeColor="White"
                    />

                        </asp:GridView>

                        <manu:PagerDataSource
                    ID="PagerDataSource2"
                    runat="server"
                
                            DataSourceID="PagerDataSource1"
                    UseCustomPageItems="True">

                        </manu:PagerDataSource>

                        <asp:ObjectDataSource
                    ID="ObjectDataSource1"
                    runat="server"
                    TypeName="IPDataDAL"
                
                            SortParameterName="sortedBy"  SelectMethod="GetDataByCountry" 

                                        SelectCountMethod="CountAll"
                    EnablePaging="True"

                            MaximumRowsParameterName="maxRows" StartRowIndexParameterName="countryId" 

                                            OldValuesParameterFormatString="original_{0}">

                        </asp:ObjectDataSource>

                    </asp:Content>

The code-behind file (ASPX.CS) is:

 
                    using System;

                    using System.Collections.Specialized;

                    public partial
                    class CustomPageItems
                : System.Web.UI.Page

                    {

                        protected void
                Page_Load(object sender, 
                    EventArgs e)

                        {

                            // the first time, set the custom
                        pages items

                            if (!IsPostBack) {

                                string
                    image = "<img src='images/{0}.gif' />";

                                StringCollection
                    customPages = new StringCollection();

                                // adds each image
                        to the collection of custom page items

                                foreach
                    (string code in
                    Countries.codes) {

                                    customPages.Add(String.Format(image,
                    code));

                                }

                                // set the custom
                        page items for each PagerDataSource

                                PagerDataSource1.CustomPageItems.AddRange(customPages);

                                PagerDataSource2.CustomPageItems.AddRange(customPages);

                            }

                        }

                    }