C# - Add Custom Control To A Placeholder All Controls

I've created a usercontrol in asp.net webforms (c#) called 'Article' which contains a general layout for an article and has a public property called datasource. the datasource will be populated by a subsonic (DAL) activerecord. In the controls pre-render event it will read the record and populates the labels. I think this is a flexible solution with easy maintenance. My problem however is that when I try to add the control to a placeholder all my controls like labels, literals and the like receive a null reference exception. I'm trying to spawn the controls as followed:

foreach (DAL.Article item in coll)
{
p7.Controls.General.Article.Article article = new p7.Controls.General.Article.Article();
article.datasource = item;
phContent.Controls.Add(article);
}

Is there something I've completely missed? It's driving me crazy heheh! Another question is do you guys know if this method will have a big impact on performance. I'm only adding 10 of those article controls per page.