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.
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();
CategoryRepeater.DataSource = ds;
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,
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");
I got the below output when I viewed the web-form in my browser.
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.
Nish is a real nice guy who has been writing code since 1990 when he first got his hands on an 8088 with 640 KB RAM. Originally from sunny Trivandrum in India, he has been living in various places over the past few years and often thinks it’s time he settled down somewhere.
Nish has been a Microsoft Visual C++ MVP since October, 2002 - awfully nice of Microsoft, he thinks. He maintains an MVP tips and tricks web site - www.voidnish.com
where you can find a consolidated list of his articles, writings and ideas on VC++, MFC, .NET and C++/CLI. Oh, and you might want to check out his blog on C++/CLI, MFC, .NET and a lot of other stuff - blog.voidnish.com
Nish loves reading Science Fiction, P G Wodehouse and Agatha Christie, and also fancies himself to be a decent writer of sorts. He has authored a romantic comedy Summer Love and Some more Cricket
as well as a programming book – Extending MFC applications with the .NET Framework
Nish's latest book C++/CLI in Action
published by Manning Publications is now available for purchase. You can read more about the book on his blog.
Despite his wife's attempts to get him into cooking, his best effort so far has been a badly done omelette. Some day, he hopes to be a good cook, and to cook a tasty dinner for his wife.