basic stuff of event callback

[labmaster]

Hi,

I just got to know the useful technique event callback with Labview. so I want to explore it further as a beginner.

I found the basic example at https://decibel.ni.com/content/docs/DOC-9161.

In seeing the attached example, I have a question in construction of the components in "Elasped Event Callback.vi".
There some control inputs (variables) and message box without any wiring or functional routine.
For example, "User Parameter" or "Event Data" is mandatory?

Can you tell me the rule of thumb in making the file?

Best,

Lee

[Bob_Schor]

Sorry -- there was no message at the link you included ("The item does not exist. It may have been deleted.").

[Dennis_Knutson]

The link has an extra period at the end. Just needs to be deleted.

[paul_cardinale]

The controls and the connections to the pane must match the specific callback invokation.

The best way to start creating a callback VI is to right-click on "VI Ref" of the "Reg Event Callback" node and select "Create Callback VI".

[labmaster]

Dear all,

I just wrote the code for WebBrowser container in .NET.
I got to know I need to wait for sometime to finish loading of webpage.
I found "ReadyState" property was helpful but need to use "DocumentCompleted" event for my complicated work.
(http://msdn.microsoft.com/en-us/library/system.windows.forms.webbrowser.documentcompleted(v=vs.110)....

However, I am a beginner for the Event Callback technique.
I tried to realize it by using some temporal variable which was just initialized before using it.
But I believe there is a simple method to check if "eventstatus" is OK.

Can you suggest how to use callback event in simple or update my code?

labmaster

[tst]

---

@labmaster wrote:

I tried to realize it by using some temporal variable which was just initialized before using it.
But I believe there is a simple method to check if "eventstatus" is OK.

Can you suggest how to use callback event in simple or update my code?

---

I don't know if you would consider this simple, but you can create a user event in the caller and register for it, then pass the event reference to the callback VI as the user parameter and generate the event in the callback VI. This will give you an event in the main VI when the callback VI runs. Make sure you register for the user event before you start the callback VI to avoid a situation where you miss the event.

[labmaster]

Thanks tst,
Hard to understand your suggestion for me but I would like to understand it.
Can you explain it in detail with an example? I couldn't find some good example in this field.

[tst]