Solved

check if an event is hooked?

Posted on 2008-10-07
6
762 Views
Last Modified: 2013-11-26
Hi experts

I have a BindingSource which has the event CurrentChanged.

Now have to hook/unhook this event dynamically in my code. This alone wouldn't be a problem.
But how can I check if the CurrentChanged event is hooked up?

I tried

if(this.MyBindingSource.CurrentChanged == null)
{

}

but this gives an error which says that I can use CurrentChanged only with += or -=
I'm using .NET 2.0, VS2008, WinForms

Thanks
0
Comment
Question by:Arikael
6 Comments
 
LVL 13

Expert Comment

by:crazyman
ID: 22658448
Not usre exactly but take a look at

this.Events[eventname].GetInvocationList().Length
0
 
LVL 13

Expert Comment

by:SameerJagdale
ID: 22658451
Sample events:

this.Init += new EventHandler(Default3_Init); // to add
this.Init -= new EventHandler(Default3_Init); // to remove
0
 
LVL 13

Expert Comment

by:crazyman
ID: 22658456
0
3 Use Cases for Connected Systems

Our Dev teams are like yours. They’re continually cranking out code for new features/bugs fixes, testing, deploying, testing some more, responding to production monitoring events and more. It’s complex. So, we thought you’d like to see what’s working for us.

 
LVL 13

Expert Comment

by:SameerJagdale
ID: 22658460
you can further check
if (this.Init != null) { .. event is hooked }  else { event is not hooked .. }
0
 
LVL 26

Accepted Solution

by:
Anurag Thakur earned 500 total points
ID: 22658514
I tried your code and got the same exception (not with binding source but with normal button control)
i am assuming that the inbuilt microsoft controls dont allow you from checking whether the event has been subscribed to or not

in this case i will recommend you to use a variable holding how many events have been hooked to and when ever a new event is hooked the value will be incremented and vice versa
0
 
LVL 3

Author Comment

by:Arikael
ID: 22658563
@crazyman

your code gives me the same exception as noted in my question.
it seems that you can't check whether the event has been subscribed to or not (see ragi0017's post).

Until now I just "unhooked" my event before I hooked it.
0

Featured Post

DevOps Toolchain Recommendations

Read this Gartner Research Note and discover how your IT organization can automate and optimize DevOps processes using a toolchain architecture.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

We all know that functional code is the leg that any good program stands on when it comes right down to it, however, if your program lacks a good user interface your product may not have the appeal needed to keep your customers happy. This issue can…
Real-time is more about the business, not the technology. In day-to-day life, to make real-time decisions like buying or investing, business needs the latest information(e.g. Gold Rate/Stock Rate). Unlike traditional days, you need not wait for a fe…
This tutorial gives a high-level tour of the interface of Marketo (a marketing automation tool to help businesses track and engage prospective customers and drive them to purchase). You will see the main areas including Marketing Activities, Design …
With Secure Portal Encryption, the recipient is sent a link to their email address directing them to the email laundry delivery page. From there, the recipient will be required to enter a user name and password to enter the page. Once the recipient …

809 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question