Asp.net's AutoEventWireup and reflection?

Question

AutoEventWireup uses reflection searching page methods by page_eventName

msdn

When AutoEventWireup is true, handlers are automatically bound to events at run time based on their name and signature. For each event, ASP.NET searches for a method that is named according to the pattern Page_eventname, such as Page_Load or Page_Init.

Question :

Does he do it for every request ?

I looked in the temporary internet files (at Microsoft.net folder...) to see if he saves another file which contains explicit handler attachment - and couldn't find any .

Answer 1

It seems that ASP.NET uses cache for that as @Marc said. See internal TemplateControl.HookUpAutomaticHandlers.

A part of this method by using dotPeek:

internal void HookUpAutomaticHandlers()
{
  ...
  object obj = TemplateControl._eventListCache[(object) this.GetType()];
  if (obj == null)
  {
    lock (TemplateControl._lockObject)
    {
      obj = TemplateControl._eventListCache[(object) this.GetType()];
      if (obj == null)
      {
        IDictionary local_1_1 = (IDictionary) new ListDictionary();
        this.GetDelegateInformation(local_1_1);
        obj = local_1_1.Count != 0 ? (object) local_1_1 : TemplateControl._emptyEventSingleton;
        TemplateControl._eventListCache[(object) this.GetType()] = obj;
      }
    }
  }
  ...

Private GetDelegateInformation method is responsible for creating delegates for the control. TemplateControl._eventListCache is a Hashtable which holds delegates per template control.

So, answering your question:

Does he do it for every request ?

The answer is no. ASP.NET does it once to populate this Hashtable, and then uses cached values.