Question

I am using a singleton pattern for a global event manager class that is not handling exceptions in an acceptable manner.

If an exception is thrown in the code called by one of the events being executed, I always get a Exception has been thrown by the target of an invocation. error. This error contains no information related to the original exception, making it extremely difficult to debug any errors.

Is there some way to pass the original exception information back to the event manager?

public class ApplicationSettings
{
    private static EventManager _manager = new EventManager();

    public static EventManager EventManager
    {
        get { return _manager; }
    }
}

The event manager class:

public class EventManager
{
    public event EventHandler<ReportExecutionArgs> ExecuteReportCurrentPage;
    public event EventHandler<ReportExecutionArgs> ExecuteReportNewPage;

    public virtual void OnExecuteReportCurrentPage(object sender, ReportExecutionArgs e)
    {
        try
        {
            if (this.ExecuteReportCurrentPage != null)
                this.ExecuteReportCurrentPage(sender, e);
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.ToString());
        }
    }

    public virtual void OnExecuteReportNewPage(object sender, ReportExecutionArgs e)
    {
        try
        {
            if (this.ExecuteReportNewPage != null)
                this.ExecuteReportNewPage(sender, e);
        }
        catch(Exception ex)
        {
            MessageBox.Show(ex.ToString());
        }
    }
}

Some other class will handle these events

ApplicationSettings.EventManager.ExecuteReportNewPage += new EventHandler<ReportExecutionArgs>(reportOpenedNewPage);

private void reportOpenedNewPage(object sender, ReportExecutionArgs e)
    {
        //something in this code throws an error
        LitePage page = new LitePage();
        _tabs.AddPage(page);
        Report report = setReport(page, e);
    }

EDIT

Just to clarify, the try/catch blocks in the OnExecuteReport methods are not catching the exception.

Answer 1

A TargetInvocationException such as the one you describe will almost always have the originating exception in it’s InnerException.