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Editorial Team
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Asked: 2026-06-10T02:47:33+00:00

I have one WinForms control project that produces a dll. There is a second

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I have one WinForms control project that produces a dll. There is a second dll project (also winforms control) that uses the first project. There is a third winforms project, this time a form, that uses the second project. So [Third Project] <>——> [Second Project] <>——–> [First Project]

The first project exposes a static event. I’m trying to subscribe to that event from the third project. The event stays as null (not subscriptions) after the += call.

Why is it not subscribing? Is it because the Winforms controls have their own thread? The FirstProject user control is created on the fly at some point in time. But I will expect the static to work correctly, without doing anything else,

Project 1

namespace Something
{
  public partial class FirstClass : UserControl
  {
    ...
    public delegate void EventHandler();
    public static event EventHandler MyEvent;
    ...
  }
}

Project 3

namespace Another
{
  public partial class ThirdClass : Form
  {
     ...
     public ThirdClass()
     {
       ....
       Something.FirstClass.MyEvent += new Something.FirstClass.EventHandler(MyHandler);
     }
     public void MyHandler()
     {
     }
     ...
   }
 }

EDIT
I have created a small application with the basics to get the three projects and the static event. And it works. Therefore something else is going on.

EDIT 2
The dll that contained the first project, the one with the event, was being loaded twice. I have just added an alias, but didn’t help. And still will not explain when just after the += the event is still null.

EDIT 3 I transformed the event so I have the add/remove accessors pair. It does enter into the add. The Handler method gets the value correctly (and therefore no null), but once it goes outside, is null again.

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1 Answer

  1. Editorial Team

    And the reason will be in my EDIT 2. Because is a static event, loading twice the dll (two different paths) was creating two different static events (or two different handlers). My EDIT 3 clearly showed that the event was being subscribed to.

    Once I forced the third project (the one subscribing to the static event) to load the dll from the same location as the project creating the event (I didn’t wanted to use the GAC), all worked.

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