A few posts ago, I mentioned that I am currently giving a classroom training on ASP.NET. People attending are currently working on a project I gave them, and today one of them came up to me with a strange problem...
Here's the situation: in VS 2008, a web page was created containing 2 controls: a DataList and a DataPager. This DataPager serves as the paging control for the DataList. Databinding is done in the codebehind:
protected void Page_Load(object sender, EventArgs e) {
ListView1.DataSource = NorthwindDataSource;
ListView1.DataBind();
}
This works perfectly! When the page is rendered in a brwoser window, data is shown in the DataList control. Now, when testing the DataPager, something strange happens: when a page number is clicked, ASP.NET will process a PostBack, rendering... the same page as before! Clicking the DataPager again is the only way to really go to a different page in the result set.
Let's have a look at the ASP.NET page lifecycle... The page Load event is actually not the best place to call the DataBind() method. PreRender is a better place to call DataBind():
protected void Page_Load(object sender, EventArgs e) {
ListView1.DataSource = NorthwindDataSource;
}
protected void Page_Render(object sender, EventArgs e) {
ListView1.DataBind();
}
