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A quick guide to using nested repeaters in ASP.NET

, 19 Feb 2004 CPOL 382K 4.2K 68
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Using nested repeaters in ASP.NET with an XML data store

Introduction

I've never really been much of a web-developer and never thought I'd find web-development all that interesting. But I must say I've been quite fascinated by what little ASP.NET I've done up till now, which is not a lot to be honest. One control I found particularly useful was the Repeater control, but I struggled a little when I tried to implement nested repeaters using an XML file as the data store. Eventually, the solution turned out to be embarrassingly easy, and I thought I'd write a little article for other first-timers who might encounter the same annoying situation I did.

Note to readers

I assume that you already know how to use a Repeater control. This article only shows you how to implement nested repeaters and will not attempt to explain repeaters in general.

Example

I am going to demonstrate a simple ASP.NET web application that will list out a Cricket World XI using an XML file as the input-data. Eventually, modification of the team simply involves a change in the XML file with no changes required either in the aspx pages or in the code-behind files.

My XML file

Essentially I have four categories - and each category has one or more players.

Implementing nested repeaters

I am going to list the categories first and inside each category I will list the players under that category. Lets first add the outter repeater that will list the categories.

We now add the inner repeater to the <ItemTemplate> tag of the outter repeater.

Writing the code-behind code

Alright, I know that "code-behind code" sounds weird, but I couldn't think of anything better sounding and if anyone has any better ideas, please drop me a line. Anyway we setup the first repeater in the Page_Load event handler as usual.

private void Page_Load(object sender, System.EventArgs e)
{
    DataSet ds = new DataSet();
    ds.ReadXml(MapPath("./XMLFile1.xml"));
    CategoryRepeater.DataSource = ds;
    CategoryRepeater.DataBind();
}

For setting up the outter repeater, we handle the ItemDataBound event of the Repeater class which is raised when an item is data-bound but before it is rendered on the page. We now get a reference to the PlayerRepeater control using RepeaterItem.FindControl and set its data source using CreateChildView and the automatic relation that's made for us - category_cricketer. By the way I was quite impressed by that, I never expected automatic relations to be created based on the XML. Pretty cool I think!

private void CategoryRepeater_ItemDataBound(object sender, 
    System.Web.UI.WebControls.RepeaterItemEventArgs e)
{
    RepeaterItem item = e.Item;
    if( (item.ItemType == ListItemType.Item) ||
        (item.ItemType == ListItemType.AlternatingItem) )
    {
        PlayerRepeater = (Repeater) item.FindControl("PlayerRepeater");
        DataRowView drv = (DataRowView)item.DataItem;
        PlayerRepeater.DataSource = drv.CreateChildView("category_cricketer");
        PlayerRepeater.DataBind();
    }
}

That's all.

The output

I got the below output when I viewed the web-form in my browser.

Conclusion

Feedback and criticism is welcome as usual. I'd also like to thank Aravind Corera (Chennai based C# MVP) who gave me the right URLs to solve this problem when I was tearing my hair out in frustration.

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

Nish Nishant

United States United States
Nish Nishant is a Software Architect/Consultant based out of Columbus, Ohio. He has over 15 years of software industry experience in various roles including Lead Software Architect, Principal Software Engineer, and Product Manager. Nish is a recipient of the annual Microsoft Visual C++ MVP Award since 2002 (13 consecutive awards as of 2014).

Nish is an industry acknowledged expert in the Microsoft technology stack. He authored
C++/CLI in Action for Manning Publications in 2005, and had previously co-authored
Extending MFC Applications with the .NET Framework for Addison Wesley in 2003. In addition, he has over 140 published technology articles on CodeProject.com and another 250+ blog articles on his
WordPress blog. Nish is vastly experienced in team management, mentoring teams, and directing all stages of software development.

Contact Nish : You can reach Nish on his google email id voidnish.

Website and Blog

Comments and Discussions

 
QuestionNested Repeater with parametr Pin
Member 115723061-Apr-15 1:17
memberMember 115723061-Apr-15 1:17 
AnswerRe: Nested Repeater with parametr Pin
Btihin8-Apr-15 1:37
memberBtihin8-Apr-15 1:37 
QuestionGood Article Pin
Alireza_136219-Mar-13 23:45
memberAlireza_136219-Mar-13 23:45 
QuestionPossible to include paging? Pin
Tyng20-Jan-13 15:24
memberTyng20-Jan-13 15:24 
QuestionA better Tutorial here Pin
tim cadieux26-Jul-12 7:50
membertim cadieux26-Jul-12 7:50 
GeneralBetter Way!! Pin
imsathy21-Jan-08 0:40
memberimsathy21-Jan-08 0:40 
GeneralRe: Better Way!! Pin
Maciej Pilichowski6-Mar-11 0:31
memberMaciej Pilichowski6-Mar-11 0:31 
GeneralRe: Better Way!! Pin
Marco Bertschi4-Mar-13 8:36
memberMarco Bertschi4-Mar-13 8:36 
QuestionI have a problem when use printed review to check nested repeater aspx pages Pin
YingHsuan26-Nov-07 0:02
memberYingHsuan26-Nov-07 0:02 
AnswerRe: I have a problem when use printed review to check nested repeater aspx pages Pin
YingHsuan27-Nov-07 5:47
memberYingHsuan27-Nov-07 5:47 
GeneralWith tableAdapter instead of xml file Pin
werge14-Sep-07 11:14
memberwerge14-Sep-07 11:14 
GeneralNested Repeaters Pin
remya3003@yahoo.com22-Jun-06 18:36
memberremya3003@yahoo.com22-Jun-06 18:36 
GeneralProblem in Converting Pin
kevinbhavasar3-Apr-06 2:18
memberkevinbhavasar3-Apr-06 2:18 
Generali want to bind to a table not xml file with teh same issue title and users under tile Pin
GiiiO9-Nov-05 0:28
memberGiiiO9-Nov-05 0:28 
Generali want to bind to a table not xml file with teh same issue title and users under tile Pin
GiiiO9-Nov-05 0:28
memberGiiiO9-Nov-05 0:28 
GeneralRequires at least two Child Nodes Pin
javafreddie6-Apr-05 16:55
memberjavafreddie6-Apr-05 16:55 
GeneralRe: Requires at least two Child Nodes Pin
7.e.Q3-Jul-07 10:06
member7.e.Q3-Jul-07 10:06 
GeneralThis code cant be complete Pin
Anonymous31-Mar-05 4:33
sussAnonymous31-Mar-05 4:33 
GeneralRe: This code cant be complete Pin
Jeff Lehmer30-Sep-06 10:45
memberJeff Lehmer30-Sep-06 10:45 
GeneralRe: This code cant be complete Pin
Alex Stephens7-Jan-13 3:32
memberAlex Stephens7-Jan-13 3:32 
GeneralNested User Controls Pin
<a href='http://www.miszou.com/'>Miszou</a>14-Feb-05 15:05
memberMiszou14-Feb-05 15:05 
Generalneed more explanation. Pin
purplerain22-Sep-04 11:20
memberpurplerain22-Sep-04 11:20 
GeneralAn alternative Pin
Ian Darling21-Feb-04 2:30
memberIan Darling21-Feb-04 2:30 
I've you've got a DataSet with two DataTables and appropriate DataRelations set up, you can DataBind the DataSource in the ASP.NET code directly using the GetChildRows function.

I had to write several ASP.NET reports sometime ago with multiple levels of nesting (up to 9!), and found that the fastest and easiest way to do it was to have a hefty DataSet and DataTables that covered the levels of nesting.

For your example, I would have had two DataTables:
Table 1 ("PlayerTypes"):
PlayerType
----------
Bowlers
Batsmen
Allrounders
WicketKeeper
Table 2 ("Players"):
PlayerType   Player
----------   ------------
Bowlers      Wasim Akram
Batsmen      Geoff Boycott
Batsmen      Sunny Gavaskar
Bowlers      Michale Holding
etc.....
Set up a DataRelation between them (like myDataSet.Relations.Add("PlayerTypesRel", myDataSet.Tables["PlayerTypes"].Column["PlayerType"], myDataSet.Tables["Players"].Column["PlayerType"])

Then the nexted repeaters look like (simplified from HTML lists to bold playertypes and italic players):
<asp:repeater id="PlayerTypesRepeater" runat="server">
<itemtemplate>
    <b><%# DataBinder.Eval(Container.DataItem, "PlayerType") %></b>
    <asp:repeater id="PlayersRepeater" runat="server"
            datasource='<%# Container.DataItem.Row.GetChildRows("PlayerTypesRel") %>'>
    <itemtemplate>
        <i><%# DataBinder.Eval(Container.DataItem, "Player") %></i>
    </itemtemplate>
    </asp:repeater>
</itemtemplate>
</asp:repeater>
(also note that after the first level of nesting, the RowView changes to a Row too, so you use DataItem.GetChildRows instead of DataItem.Row.GetChildRows)

This is from memory and untested, but it's essentailly how I did it, and it worked great.

Hope that is useful Smile | :)


Ian Darling
"One of the few systems...which has had “no deaths” in the reliability requirements." - Michael Platt
GeneralRe: An alternative Pin
Scott Galloway21-Feb-04 2:39
sussScott Galloway21-Feb-04 2:39 
GeneralRe: An alternative Pin
Ian Darling21-Feb-04 2:42
memberIan Darling21-Feb-04 2:42 

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