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Extend Repeater to support DataPager

, 21 Oct 2011
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How to extend Repeater to support DataPager.

Introduction

I have seen some examples of making a Repeater to work with a DataPager like it does with the ListView control. But all examples failed when I tried them, and I spent some time to get this to work. Here is my solution.

Using the code

First, create a Custom Web Control with the name DataPagerRepeater. Inherit it from Repeater and include the System.Web.UI.WebControls.IPageableItemContainer namespace (this requires that you add a reference to System.Web.Extensions).

Add this code:

[ToolboxData("<{0}:DataPagerRepeater runat="server" 
   PersistentDataSource=true></{0}:DataPagerRepeater>")]

public class DataPagerRepeater : Repeater, 
       System.Web.UI.WebControls.IPageableItemContainer, INamingContainer
{

    public int MaximumRows { get { return ViewState["_maximumRows"] != null ? 
                                 (int)ViewState["_maximumRows"] : -1; } }
    public int StartRowIndex { get { return ViewState["_startRowIndex"] != null ? 
                              (int)ViewState["_startRowIndex"] : -1; } }
    public int TotalRows { get { return ViewState["_totalRows"] != null ? 
                               (int)ViewState["_totalRows"] : -1; } }

    public bool PersistentDataSource { 
        get { return ViewState["PersistentDataSource"] != null ? 
              (bool)ViewState["PersistentDataSource"] : true; }
        set { ViewState["PersistentDataSource"] = value; }
    }

    protected override void LoadViewState(object savedState)
    {
        base.LoadViewState(savedState);

        if (Page.IsPostBack)
        {
            if (PersistentDataSource && ViewState["DataSource"] != null)
            {
                this.DataSource = ViewState["DataSource"];
                this.DataBind();
            }
        }
    } 

    public void SetPageProperties(int startRowIndex, int maximumRows, bool databind)
    {
        ViewState["_startRowIndex"] = startRowIndex;
        ViewState["_maximumRows"] = maximumRows;

        if (TotalRows > -1)
        {
            if (TotalRowCountAvailable != null)
            {
                TotalRowCountAvailable(this, 
                   new PageEventArgs((int)ViewState["_startRowIndex"], 
                   (int)ViewState["_maximumRows"], TotalRows));
            }
        }
    }

    protected override void OnDataPropertyChanged()
    { 
        if (MaximumRows != -1)
        {
            this.RequiresDataBinding = true;
        }
        else
            base.OnDataPropertyChanged();
    }

    protected override void RenderChildren(HtmlTextWriter writer)
    {
        if (MaximumRows != -1)
        {
            foreach (RepeaterItem item in this.Items)
            {
                if (item.ItemType == ListItemType.Item || 
                    item.ItemType == ListItemType.AlternatingItem)
                {
                    item.Visible = false;

                    if (item.ItemIndex >= (int)ViewState["_startRowIndex"] && 
                        item.ItemIndex <= ((int)ViewState["_startRowIndex"] + 
                          (int)ViewState["_maximumRows"]))
                    {
                        item.Visible = true;
                    }
                }
                else
                {
                    item.Visible = true;
                }
            }
        }
        base.RenderChildren(writer);
    }

    public override void DataBind()
    { 
        base.DataBind();

        if (MaximumRows != -1)
        {
            int i = 0;
            foreach (object o in GetData())
            {
                i++;
            }
            ViewState["_totalRows"] = i;

            if(PersistentDataSource)
                ViewState["DataSource"] = this.DataSource;
            SetPageProperties(StartRowIndex, MaximumRows, true);
        }
    }

    protected override System.Collections.IEnumerable GetData()
    {
        return base.GetData();
    }

    public event System.EventHandler<PageEventArgs> TotalRowCountAvailable;
}

Build and use like this in an ASP.NET Form:

<cc1:DataPagerRepeater ID="rep1" 
    runat="server" PersistentDataSource="true"> 
<HeaderTemplate > <div></HeaderTemplate> 
<ItemTemplate> 
 <div >
 <%# Eval("Value") %>
 </div>
 </ItemTemplate> 
<FooterTemplate></div></FooterTemplate> 
</cc1:DataPagerRepeater> 

<asp:DataPager ID="DataPager1" 
  PagedControlID="rep1" PageSize="2" runat="server">
<Fields>
<asp:NextPreviousPagerField ButtonType="Button" ShowFirstPageButton="True" 
   ShowNextPageButton="False" ShowPreviousPageButton="False" />

<asp:NumericPagerField />
<asp:NextPreviousPagerField ButtonType="Button" ShowLastPageButton="True" 
        ShowNextPageButton="False" ShowPreviousPageButton="False" />
</Fields>

</asp:DataPager>

And in the code-behind:

protected void Page_Load(object sender, EventArgs e) 
{
    if(!IsPostBack)
    {
        System.Collections.SortedList SL = new System.Collections.SortedList();

        SL.Add("val1","Text1");
        SL.Add("val2","Text2");
        SL.Add("val3","Text3");
        SL.Add("val4","Text4");
        SL.Add("val5","Text5");
        SL.Add("val6","Text6");
        SL.Add("val7","Text7");
        SL.Add("val8","Text8");
        SL.Add("val9","Text9");

        rep1.DataSource = SL;
        rep1.DataBind();
    } 
}

That's all!

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

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About the Author

Mr Orange
Software Developer (Senior) Sigma IT & Management
Sweden Sweden
Working with web application development since 1999.
Developer of the CMS product Publech (www.publech.com) and a large range of other Publech modules.
 
Involved in developing the largest non commercial website in Sweden the Swedish Public Employment Service (www.ams.se)

Comments and Discussions

 
Generalone step behind PinmemberMember 778573324-May-11 0:19 
GeneralRe: one step behind PinmemberMr Orange26-May-11 20:54 
GeneralFantastic work Pinmemberkcabrams22-Sep-10 8:44 
QuestionPagingInDataSource Issue PinmemberChadBoettcher29-Jun-10 14:15 
Hi,
 
First off, thanks for the great example. It's almost exactly what I needed.
 
I'm trying to implement the version of the control that you have at http://www.publech.com/DataPagerRepeater.zip[^].
 
My understanding is that when the FetchingData event is raised, I should re-bind the repeater with the next or previous page of data and set the total records. The problem I'm having is that that the FetchingData event is raised before the new StartRowIndex value is set by the DataPager so essentially, all I can do is rebind the previous page of data.
 
What I ended up doing is checking for IsPostBack in the SetPageProperties method (because it seems that the DataPager eventually calls it) and doing the same checks you did in OnLoad then calling FetchingData there. Paging now works correctly with the intended page of data but only because FetchData is now called twice, thus doubling my calls to the database.
 
Is this working for anyone? Is there a way call FetchingData only after the new page index has been set by the DataPager?
 
Thanks,
 
Chad
AnswerRe: PagingInDataSource Issue PinmemberChadBoettcher26-Jul-10 17:52 
GeneralDataPagerRepeater inside UpdatePanel Pinmemberran97-Jun-10 10:49 
GeneralRe: DataPagerRepeater inside UpdatePanel PinmemberMr Orange7-Jun-10 21:47 
GeneralRe: DataPagerRepeater inside UpdatePanel Pinmemberran98-Jun-10 9:40 
GeneralRe: DataPagerRepeater inside UpdatePanel PinmemberMr Orange8-Jun-10 21:30 
GeneralRe: DataPagerRepeater inside UpdatePanel Pinmemberran914-Jun-10 7:26 

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