Check if Usercontrol previously loaded on page

Question

Is there a way, within a .Net user control, to check if the control has been previously loaded on the page?

I thought about trying storing a variable in a .Net session variable to track each control as it loads, then disposing of the variable in the page pre-render event. It seems to me that there has to be a better way to accomplish this.

The reason I need to do this is because the usercontrols are loaded as sublayouts within sitecore, and I have no idea how many times a content author may have added the control to the page. If it is the first time the control is being called to the page I need to add a write out a div tag for a 3rd party service. If the div tag occurs more than once, the 3rd party service, gawks.

Answer 1

Just use HttpContext.Current.Items to keep the information about loaded control.

As the name indicates, HttpContext.Current is only for a single web request. No need to worry about disposing or clearing old data.

if (HttpContext.Current.Items["I was here"] == null) 
{
    // do custom div magic
    HttpContext.Current.Items["I was here"] = true;
}