以编程方式在C＃中创建ASP.NET PlaceHolders

I am trying to create a loop that will write some data and add an ASP.NET placeholder to the bottom of the each looped item that I can reference later through other events. The code runs, but the placeholder isn't being added to the ASP.net page. I verified this by looking at the source in the browser. I am not seeing any of the breaks and the label text isn't displaying. Any thoughts/suggestions would be appreciated. I am trying to create a loop that will write so