calling the other functions when an exception is thrown - C# delegates

Question

if a delegate points to 5 methods, when delegate is invoked an excpetion happens in first method. since the exception happens the rest of the 4 functions cannot be called. How to make the delegate to call other functions even when exceptions happpens

Answer 1

You'd need to use Delegate.GetInvocationList to basically split the delegate into the individual actions, and call each in turn with a catch clause to handle the exceptions.

For example:

Action[] individualActions = (Action[]) multicast.GetInvocationList();

foreach (Action action in individualActions)
{
    try
    {
        action();
    }
    catch (Exception e)
    {
        // Log or whatever
    }
}

You may want to only catch specific types of exception, of course.

Answer 2

You will have to call (Invoke) the subscribed handlers yourself, inside a try/catch block. You can get the list with GetInvocationList() .

The better solution requires control over the handlers: They should not throw.

The rough code for handling the exceptions:

        foreach (Delegate handler in myDelegate.GetInvocationList())
        {
            try
            {
                object params = ...;
                handler.Method.Invoke(handler.Target, params);
            }
            catch(Exception ex)
            {
                // use ex
            }
        }

Answer 3

May be following code will help you understand how to do that.

 public class DynamicInvocation
{
    public event EventHandler SomeEvent;
    public void DoWork()
    {
        //Do your actual code here
        //...
        //...
        //fire event here
        FireEvent();
    }

    private void FireEvent()
    {
        var cache = SomeEvent;
        if(cache!=null)
        {
            Delegate[] invocationList = cache.GetInvocationList();
            foreach (Delegate @delegate in invocationList)
            {
                try
                {
                    @delegate.DynamicInvoke(null);
                }
                catch
                {

                }
            }
        }
    }
}