I have an application that uses a NotifyIcon in the tray to hide/restore the application, as well as pop up notices to the user of application events. My application has a notification queue, and I use the NotificationIcon.BalloonTipClosed event to determine when to reset the balloon and show the next notification (if there's one in the queue).
This method seems to work great in both usual causes (user lets the balloon close itself when it times out, and user clicks "X" in balloon to force it to close), but there's a third case where BalloonTipClosed doesn't get called:
Notification balloon pops up
While it's visible, user right-clicks on notification icon to bring up context menu, causing the balloon to disappear
The BalloonTipClosed event doesn't get triggered in this instance - I figure it's a bug in the framework (I'm using 2.0), but does anybody have an idea around this? If I don't get this event, my application always thinks there's a balloon visible (I have a boolean that prevents it from displaying multiple balloons at once), and it will never show another icon again, as long as it's running.
This belongs as a comment to Aarons answer, but I am not allowed to comment yet.
If you handle the BalloonTipClicked and MouseClick events on the NotifyIcon (as well as the BalloonTipClosed) then you can capture all the ways the balloon can close. The only thing you have to be aware of is that several scenerios will trigger multiple events, so be sure to code around that (something like isClosed = true, and then reset that when a new balloon is displayed).
In the event handler for the BalloonTipClicked Event, I would check to see if the right mouse button was clicked, and if it was set the boolean to false.
Here's what I ended up doing, though I don't particularly like this solution. I added a second timer to the form and set it for 10 seconds. When a notification pops up (when I pop one), I start the timer, and then in BalloonTipClosed, I stop it. If the timer ticks (meaning that BalloonTipClosed hasn't run yet), I display the next tip manually.
The result is that if it hasn't fired yet, I take care of it. However, I'm open to better solutions if anybody has one.
I think this post from Raymond Chen about balloon notifications may help you:
http://blogs.msdn.com/oldnewthing/archive/2009/05/04/9585032.aspx
Related
I am currently working on a LabVIEW project and have found myself stuck on how to make a while loop exit when I press the abort (stop) button. For a simple while loop I understand how to do this - but the problem is that this while loop is nested inside of an event structure and I'm guessing that the button cannot be pressed while the loop is executing. Attached here is a picture of part of my code (that contains this specific event case which is causing me problems): To spend a little more time explaining what the problem is - I think the code is doing what I want it to do (namely output a set of commands in a repeated cycle with a wait timer) but I cannot stop the code mid cycle (pressing the abort button with my mouse does nothing - as in the button doesn't show it being pressed and the indicator shows no change, I also can't use any other functionality of my program during the cycle which I'm assuming is related). And I do not want to stop the LabVIEW program from running entirely - just the code inside the while loop pictured above. This is what the front panel is configured too for completeness:
Essentially what I want to happen is the while loop to execute when I press DWG and in the middle of the cycle be able to abort it. Sorry if my code seems a little messy. Additionally, I've tried the same code with a for loop originally (via a conditional terminal so it could stop early) and that didn't work either. Thanks for any help I appreciate it!
Your problem is that inside the event structure, by default the UI is frozen so no UI actions (keyboard/mouse/etc) are processed until you exit that frame.
Option 1. You can right click the Event Structure and select "Edit events handled by this case" dialog and then uncheck the "Lock panel" checkbox -- that will allow the UI to be live while you are in that frame. I do not recommend this solution generally unless you have an extremely simple user interface because it leads to the user being able to change controls without the events behind those controls being processed (not a good UI experience for users). But if the UI is simple enough, that works.
Option 2. You can create a user event that is the code you want inside your While Loop. When the Deg Wait Go button is pressed, use the "Generate User Event" node to trigger that event. Do the same thing in the user event case so that the event re-triggers itself if and only if the Abort button has not been pressed.
Option 3. Create a separate loop OUTSIDE your UI loop that does your processing with some sort of command queue running between the UI loop and that other loop. The other loop moves into various states at the request of the UI loop... it's the one that does nothing until it receives a "go" message and then keeps looping until it receives a "stop" message. You can Google "queued message handler" for extensive details of this solution. This is the most common solution for complex UI requirements, especially useful for separating concerns of the UI code from the execution code.
I am using simple event handler in the while loop.
I have value change event for the boolean button. There is some code that takes 3-4 seconds to execute.
The problem is I am not able to click anything on my Front panel during this period. Is it possible to allow the user to click on other controls when event handler is working on some case (as I understand the event handler is able to collect all events and process them ASAP)?
I fully agree with Mikhail N Zakharov's answer, but anyway your problem can be easily solved by just unchecking the checkbox named Lock panel until the case for this event complates
Please see screenshot below.
PS. Once again it is not the best practise to make event structure to work for 3-4 seconds.
I think you need to restructure your application to make it more responsive. LabVIEW best development practices suggest keeping event handler code as fast as possible. One of the ways to handle this would be to send a message into the queue on the change of this Boolean control and process the queue in a separate loop.
is there anyway to capture and cancel or do something like me.activate when the show desktop event is triggered and make my form visible?
note:
The show desktop event is triggered by another app which is installed in some of my users pc. I am not trying to make my form always on top of other open windows.
Thanks in advance.
Alright, you mean to let your form stay on TopMost even if ToggleDesktop() in shell32.dll is executed.
By far I can say: there is none. They tried to experiment at codeguru but it seems there were no successfully results.
I have a Windows vb.net project that does an occasional "auto refresh" based on a 20 minute timer. I want to avoid any type of auto-refresh... if the user has manually had any interaction with the program (mouse move, click, keystroke, anything) in the past 5 minutes.
I added a global variable "Dim g_LastActivity As Date" so the timer can detect that 5 minute mark.
Is there some place to put my "g_LastActivity = NOW" line that will ensure it will happen during ANY user activity? All mouse clicks, on all buttons, all mouse moves, anywhere, all keystrokes, basically EVERYTHING.
Or is there an entirely different way to do that?
Look into Application.Idle event to see if it will fit your needs.
I have an application that searches in a database for some information.
Since the database is quite big, it sometimes takes a lot of time before the application returns the results to the interface.
I want to add some sort of spinning wheel to inform the user that the application is still searching the database and did not freeze. Once the results are returned, the wheel should disappear.
Any idea how to do this or is there a good tutorial explaining how to do this?
Have you considered changing the mouse pointer to the hourglass as this would be extremely simple to implement:
Me.Cursor = Cursors.WaitCursor
...Do your DB calls here...
Me.Cursor = Cursors.Default
However, I would agree that display a 'spinning wheel' is probably a little more user friendly and definately a lot more obvious. So, first get hold of an animated gif that suits your needs. Then create a form that has a picture box containing the image.
Once you have that you can show the form to the user and in the background do the DB work, once this has completed close the form.
Another alternative would be to use a rolling progress bar instead, so when it reaches 100% it cycles around again and keeps going until you close it.
EDIT:
One thing that I forgot to mention is that you will have to handle exception conditions. Lets say you set the cursor to wait, then an error occurs. The exception may bypass the code that resets everything. This leaves the user with a changed cursor and no means of changing it.
When I have done this kind of thing I have typically created a disposable WaitCursor class and then used something like this:
Using myWaitCursor As WaitCursor = New WaitCursor
...do something...
End Using
In the Dispose of the WaitCursor class you set the cursor back to default. The same would apply if you went down the route of using a form with an image or progress bar.
Find an animated gif of such a spinner, like this one. Put it in a PictureBox, set its Visible property to True when you start the job. Beware that you'll have to run the query in a worker thread to keep the animation alive and the user interface responsive. The BackgroundWorker class is good for that.
You could use the Environments Default wait cursor, which for Vista/7 is a circle with the outside spinning, or the XP tumbling hourglass.
You could launch your DB access on a BackgroundWorker and show an animated control such as a Marquee progress bar, or you could show a custom animation to show Busy status.