Question

Is there a concise way to safely invoke events in C#.Net. I would like to safely deal with no subscribers and exceptions subscribers might throw…

I kinda want a TryInvoke method on Delegate..ideally where I could pass an exception handler too. I am in .Net 3.5 so don’t have extension methods…

Anyway here is the boilerplate I typically use.

    void fireListChanged(List<string> paths)
    {             
        try
        {
            if (ListChanged != null)
            {
                ListChanged(paths);
            }
        }
        catch (System.Exception ex)
        {
            m_output.write(ex);
        }
    }

    public event ListStringChangedDlgt ListChanged;

Answer 1

Just use the = delegate {} pattern. The bonus compared to your solution is that it’s thread safe.

void fireListChanged(List<string> paths)
{             
    try
    {
            ListChanged(paths);
    }
    catch (System.Exception ex)
    {
        m_output.write(ex);
    }
}

public event ListStringChangedDlgt ListChanged = delegate {};

I also recommend that you use EventHandler or EventHandler<YourEventArgClass> as delegate for the event.