Why does silverlight run into an endless loop when printing document longer than 1 page? .HasMorePages = true - silverlight

My 1st question here on stackoverflow.
I am trying to print a long grid, which was dynamically generated.
pdoc.PrintPage += (p, args) =>
{
args.PageVisual = myGrid;
args.HasMorePages = false;
};
When I use args.HasMorePages = false;, it prints the first page of the grid as it should (although it takes some time, since it sends a 123MB big bitmap to the poor printer - thanks for silverlight 4's print feature implementation.).
However, when I enable printing more pages withargs.HasMorePages = true;, the printing job runs amok on the memory and sends endless copies of the first printing page of the document - effectively disabling my developer machine. Even if the grid is only 2 pages long.
Why does this happen?
What is a possible workaround here? All I found on the net is that SL handles printing badly, but not a real solution.

The HasMorePages property indicates to silverlight printing that you have a least one more page to print. The PrintPage page event fires for each page to be printed.
Hence when you set HasMorePages to true you will get another PrintPage event, if you always set it true (as your code appears to be doing) you are creating an infinite loop.
At some point the code has to leave HasMorePages set to false.
Ultimately its up to you the developer to perform all the pagination logic and decide what appears on each page, Silverlight does not automagically do that for you.

Related

AppleScript not looping all numbers when using repeat

I am using this script to close all "Alerts" in my notification bar:
tell application "System Events"
tell process "NotificationCenter"
set numwins to (count windows)
repeat with i from numwins to 1 by -1
click button "Close" of window i
end repeat
end tell
end tell
However this doesn't close them all, even when there are no "Alert without Close button".
try catch didn't help. What's wrong?
I tested your script and it seemed to run correctly on my machine, but there is always a potential for problems when you use a repeat loop on a mutating list: in other words, a list that changes as the repeat loop progresses. Each time you close a window Notification Center changes its window list and updates the properties of the remaining windows; the script can simply lose track. I'm a little surprised it doesn't throw errors when this happens, but...
You can try this code and see if it works. rather than referring to windows by index it repeatedly tries to close the last window, ignoring any errors, and keeps on until the window count is zero or it loops 100 times (that last is to prevent an endless loop in case something goes wrong).
tell application "System Events"
tell process "NotificationCenter"
repeat 100 times
try
tell last window
click button "Close"
end tell
end try
if (count of its windows) = 0 then
exit repeat
end if
end repeat
end tell
end tell
EDIT
Per comments, the above doesn't work quite as advertised, so let's switch it over to AppleScriptObjC:
use framework "Foundation"
property NSUserNotificationCenter : class "NSUserNotificationCenter"
NSUserNotificationCenter's defaultUserNotificationCenter's removeAllDeliveredNotifications()
This seems to do the trick on my machine. Of course, NSUserNotificationCenter is deprecated as of 10.14, so this won't work forever — eventually you'll have to shift over to the notification's framework — but it should work for a few more OS versions.
EDIT 2
Per another comment, anyone working on os 10.14 or later (Mojave and Catalina, to date) can do an equivalent AppleScriptObjC routine using the UserNotifications framework, like so:
use framework "UserNotifications"
set notificationCenter to class "UNUserNotificationCenter"'s currentNotificationCenter
notificationCenter's removeAllDeliveredNotifications()
Note that I've used a slightly different syntax (merely calling class "UNUserNotificationCenter" rather than setting up a property). Both work; the property syntax is only preferable when you need to pass the class to handlers.

Coded UI - How do we find if something exists when IsVisible, Exists, TryGetClickablePoint etc all return true when I can't see the control?

I am testing a WPF application and am not privy to it's exact workings but I am finding many instances where I need to find if a control is shown. All the traditional answers on this on Stack Overflow and MS forums etc say to use one of the following ...
IsVisible,
Exists,
TryGetClickablePoint,
State (e.g. OffScreen
The problem is that for this system, many controls return true for all of those even when the control cannot be seen! They also return a point with co-ordinates (-1, -1, -1, -1) whether the control is visible or not.
The only thing I have had any success with is using a try catch finally. I try to click on the control and if that fails, I go in to the catch block. That takes 60 seconds to time out though and I am getting intermittent issues with tests that run 9 times out of 10. Maybe the constant use of try catch is causing performance issues.
Is there an approach that actually works when all the standard approaches fail? I have noticed lots of other people asking these question are also testing WPF. Is there something WPF developers are doing to hide controls that makes CodedUI think they are still present and visible etc. Are they just behind something?
Many thanks in advance.
The solution was two-fold. Firstly I had to find the element and this was not working properly with my recorded steps. The element was buried too deeply in the system under test which is WPF (XAML). Secondly I had to prove I had found the element and for this I can't use TryGetClickablePoint, Exists, Top or Width. None of them seemed to work properly at all for my element. I had to use State.
public void Assert_MyElementShown()
{
#region Variable Declarations
WpfCustom uISurfaceCustom = this.UISysUnderTestClientShWindow.UIItemCustom1.UISurfaceCustom;
WpfCustom uIYAxisLabelsCustom = new WpfCustom();
#endregion
//Find the Element using it's Container and SearchProperties
uIYAxisLabelsCustom.Container = uISurfaceCustom;
uIYAxisLabelsCustom.SearchProperties[WpfControl.PropertyNames.ClassName] = "Uia.AxisLabelControl";
uIYAxisLabelsCustom.SearchProperties[WpfControl.PropertyNames.AutomationId] = "YAxisLabels";
//Use the State to find if it's on screen or not
var state = uIYAxisLabelsCustom.State;
if (state == Microsoft.VisualStudio.TestTools.UITest.Extension.ControlStates.Default)
{
//Element is visible, do stuff here!
}
else if (state == Microsoft.VisualStudio.TestTools.UITest.Extension.ControlStates.Offscreen)
{
//The control may exist, it may have location on screen and may even
//appear to be clickable according to coded ui framework but is is NOT
//shown on the screen.
}
}
You can try this approach for your application..if control properties are showing true for viable than we can go for height and width.Means if control is not visible in UI and but still all properties are showing true than check control height and width must be in -ve number.Than we can keep a assertion like
If control.height<0
Not visible in UI

Printing on Silverlight

I am trying to print a report where we have several different components within the xaml.
By what I`ve found, when printing, you have to treat every UIelement as a single one, thus if the desiredSize is bigger than the AvailableSize you have to activate the flag HasMorePages.
But here comes the problem.
My user can write as much text as he/she wants on the grid, therefore, depending on the amount, the row expands and goes off the printable area, as you can see on the picture below.
I thought about giving a whole page to the grid, but it was to big still, which got me into a loop where the DesizedSize was always bigger than the PrintableArea.
My code is not very different from any source you find on internet when searching for Multiple Page printing.
It is based on this http://eswarbandaru.blogspot.com.au/2011/02/print-mulitple-pages-using-silverlight.html , but using Stackpanels instead of Textboxes.
Any idea?
Thank you in advance.
First you need to work out how many pages are needed
Dim pagesNeeded As Integer = Math.Ceiling(gridHeight / pageHeight) 'gets number of pages needed
Then once the first page has been sent to the printer, you need to move that data out of view and bring the new data into view ready to print. I do this by converting the whole dataset into an image/UI element, i can then adjust Y value accordingly to bring the next set of required data on screen.
transformGroup.Children.Add(New TranslateTransform() With {.Y = -(pageIndex * pageHeight)})
Then once the number of needed pages is reached, tell the printer to stop
If pagesLeft <= 0 Then
e.HasMorePages = False
Exit Sub
Else
e.HasMorePages = True
End If
Or if this is too much work, you can simply just scale all the notes to fit onto screen. Again probably by converting to UI element.
Check out this link for converting to a UI element.
http://www.codeproject.com/Tips/248553/Silverlight-converting-to-image-and-printing-an-UI
Hope this helps

UIPageViewController navigates to wrong page with Scroll transition style

My UIPageViewController was working fine in iOS 5. But when iOS 6 came along, I wanted to use the new scroll transition style (UIPageViewControllerTransitionStyleScroll) instead of the page curl style. This caused my UIPageViewController to break.
It works fine except right after I've called setViewControllers:direction:animated:completion:. After that, the next time the user scrolls manually by one page, we get the wrong page. What's wrong here?
My workaround of this bug was to create a block when finished that was setting the same viewcontroller but without animation
__weak YourSelfClass *blocksafeSelf = self;
[self.pageViewController setViewControllers:viewControllers direction:UIPageViewControllerNavigationDirectionForward animated:YES completion:^(BOOL finished){
if(finished)
{
dispatch_async(dispatch_get_main_queue(), ^{
[blocksafeSelf.pageViewController setViewControllers:viewControllers direction:UIPageViewControllerNavigationDirectionForward animated:NO completion:NULL];// bug fix for uipageview controller
});
}
}];
This is actually a bug in UIPageViewController. It occurs only with the scroll style (UIPageViewControllerTransitionStyleScroll) and only after calling setViewControllers:direction:animated:completion: with animated:YES. Thus there are two workarounds:
Don't use UIPageViewControllerTransitionStyleScroll.
Or, if you call setViewControllers:direction:animated:completion:, use only animated:NO.
To see the bug clearly, call setViewControllers:direction:animated:completion: and then, in the interface (as user), navigate left (back) to the preceding page manually. You will navigate back to the wrong page: not the preceding page at all, but the page you were on when setViewControllers:direction:animated:completion: was called.
The reason for the bug appears to be that, when using the scroll style, UIPageViewController does some sort of internal caching. Thus, after the call to setViewControllers:direction:animated:completion:, it fails to clear its internal cache. It thinks it knows what the preceding page is. Thus, when the user navigates leftward to the preceding page, UIPageViewController fails to call the dataSource method pageViewController:viewControllerBeforeViewController:, or calls it with the wrong current view controller.
I have posted a movie that clearly demonstrates how to see the bug:
http://www.apeth.com/PageViewControllerBug.mov
EDIT This bug will probably be fixed in iOS 8.
EDIT For another interesting workaround for this bug, see this answer: https://stackoverflow.com/a/21624169/341994
Here is a "rough" gist I put together. It contains a UIPageViewController alternative that suffers from Alzheimer (ie: it doesn't have the internal caching of the Apple implementation).
This class isn't complete but it works in my situation (namely: horizontal scroll).
As of iOS 12 the problem described in the original question seems to be almost fixed. I came to this question because I experienced it in my particular setup, in which it does still happen, hence the word "almost" here.
The setup I experienced this issue was:
1) the app was opened via a deep link
2) based on the link the app had to switch to a particular tab and open a given item there via push
3) described issue happened only when the target tab was not previously selected by user (so that UIPageViewController was supposed to animate to that tab) and only when setViewControllers:direction:animated:completion: had animated = true
4) after the push returning back to the view controller containing the UIPageViewController, the latter was found to be a big mess - it was presenting completely wrong view controllers, even though debugging showed everything was fine on the logic level
I supposed that the root of the problem was that I was pushing view controller very quick after setViewControllers:direction:animated:completion: called, so that the UIPageViewController had no chance to finish something (maybe animation, or caching, or something else).
Simply giving UIPageViewController some spare time by delaying my programmatic navigation in UI via
DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + 1) { ... }
fixed the issue for me. And it also made the programmatic opening of the linked item more user friendly visually.
Hope this helps someone in similar situation.
Because pageviewVC call multi childVC when swipe it. But we just need last page that visible.
In my case, I need to change index for segmented control when change pageView.
Hope this help someone :)
extension ViewController: UIPageViewControllerDelegate {
func pageViewController(_ pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {
guard let pageView = pageViewController.viewControllers?.first as? ChildViewController else { return }
segmentedControl.set(pageView.index)
}
}
This bug still exists in iOS9. I am using the same workaround that George Tsifrikas posted above, but a Swift version:
pageViewController.setViewControllers([page], direction: direction, animated: true) { done in
if done {
dispatch_async(dispatch_get_main_queue()) {
self.pageViewController.setViewControllers([page], direction: direction, animated: false, completion: {done in })
}
}
}
Another simple workaround in Swift: Just reset the UIPageViewController's datasource. This apparently clears its cache and works around the bug. Here's a method to go directly to a page without breaking subsequent swipes. In the following, m_pages is an array of your view controllers. I show how to find currPage (the index of the current page) below.
func goToPage(_ index: Int, animated: Bool)
{
if m_pages.count > 0 && index >= 0 && index < m_pages.count && index != currPage
{
var dir: UIPageViewController.NavigationDirection
if index < currPage
{
dir = UIPageViewController.NavigationDirection.reverse
}
else
{
dir = UIPageViewController.NavigationDirection.forward
}
m_pageViewController.setViewControllers([m_pages[index]], direction: dir, animated: animated, completion: nil)
delegate?.tabDisplayed(sender: self, index: index)
m_pageViewController.dataSource = self;
}
}
How to find the current page:
var currPage: Int
{
get
{
if let currController = m_pageViewController.viewControllers?[0]
{
return m_pages.index(of: currController as! AtomViewController) ?? 0
}
return 0
}
}
STATEMENT:
It seems that Apple has spotted that developers are using UIPageViewController in very different applications that go way beyond the
originally intended ones Apple based their design-choices on in the first place. Rather than using it in a gesture driven linear fashion
PVC is often used to programmatically jump to random
positions within a structured environment. So they have enhanced their implementation of UIPageViewController and the class is now calling both DataSource
callbacks
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController
after setting a new contentViewController on UIPageViewController with
[self.pageViewController setViewControllers:viewControllers direction:UIPageViewControllerNavigationDirectionForward animated:YES completion:nil];
even if an animated turn of pages rather suggests a linear progress in an e.g. page hierarchy like a book or PDF with consecutive pages. Although - I doubt that Apple from a HIG standpoint
is very fond of seeing PVC being used this way, but - it doesn't break backwards compatibility, it was an easy fix, so - they eventually did it. Actually it is just one more call of one of the two DataSource methods that is absolutely unnecessary in a linear environment where pages (ViewControllers) have already been cashed for later use.
However, even if this enhancement might come in very handy for certain use-cases the initial behavior of the class is NOT to be considered a bug. The fact that a lot of developers do - also in other
posts on SO that accuse UIPageViewController of misbehavior - rather emphasizes a widely spread misconception of its design, purpose and functionality.
Without trying to offend any of my fellow developers here in this great facility I nonetheless decided not to remove my initial 'disquisition' that clearly explains to the OP the mechanics of PVC and why his assumption is wrong that he has to deal with a bug here.
This might also be of use for any other fellow developer too who struggles with some intricacies in the implementation of UIPageViewController!
ORIGINAL ANSWER:
After having read all the answers over and over again - included the
accepted one - there is just one more thing left to say...
The design of UIPageViewController is absolutely FLAWLESS and all the
hacks you submit in order to circumvent an alleged bug is nothing but
remedies for your own faulty assumptions because you goofed it up in the
first place!!!
THERE IS NO BUG AT ALL! You are just fighting the framework. I'll explain why!
There is so much talk about page numbers and indices! These are concepts the
controller knows NOTHING about! The only thing it knows is - it is showing
some content (btw. provided by you as a dataViewController) and that it can
do something like a right/left animation in order to imitate a page turn.
CURL or SCROLL...!!!
In the pageViewController's world there only exists a current SPACE (let's call
it just this way to avoid confusion with pages and indices).
When you initially set a pageViewController it only minds about this very SPACE.
Only when you start panning its view it starts asking its DataSource what it
eventually should display in case a left/right flip should happen. When you start
panning to the left the PVC asks first for the BEFORE-SPACE and then for the
AFTER-SPACE, in case you start to the right it does it the other way round.
After the completed animation (a new SPACE is displayed by the PVC's view) the
PVC considers this SPACE as its new center of the universe and while it is at it, it
asks the DataSource about the one it still does not know anything about. In case of
a completed turn to the right it wants to know about the new AFTER space and in
case of a completed turn to the left it asks for a new BEFORE space.
The old BEFORE space (from before the animation) is in case of a completed turn to
the right completely obsolete and gets deallocated as soon as possible. The old center
is now the new BEFORE and the former AFTER is the new center. Everything just
shifted one step to the right.
So - no talk of 'which page' or 'whatever index' - just simply - is there a BEFORE or
an AFTER space. If you return NIL to one of the DataSource callbacks the PVC just
assumes it is at one extreme of your range of SPACES. If you return NIL to both
callbacks it assumes it is showing the one and only SPACE there is and will never
ever again call a DataSource callback anymore! The logic is up to you! You define
pages and indices in your code! Not the PVC!!!
For the user of the class there are two means of interacting with the PVC.
A pan-gesture that indicates whether a turn to the BEFORE/AFTER space is desired
A method - namely setViewControllers:direction:animated:completion:
This method does exactly the same than the pan gesture is doing. You are indicating the
direction (e.g. UIPageViewControllerNavigationDirectionBackward/Forward)
for the animation - if there is one intended - which in other words just means -> going to
BEFORE or AFTER...
Again - no mentioning of indices, page-numbers etc....!!!
It is just a programmatically way of achieving the same a gesture would!
And the PVC is doing right by showing the old content again when moving back
to the left after having moved to the right in the first place. Remember
- it is just showing content (that you provide) in a structured way - which is a 'single page turn' by design!!!
That is the concept of a page turn - or BOOK, if you like that term better!
Just because you goof it up by submitting PAGE 8 after PAGE 1 doesn't mean the PVC
cares at all about your twisted opinion of how a book should work. And the user of your
apps neither. Flipping to the right and back to the left should definitely result in reaching
the original page - IF done with an animation. And it is up to YOU to correct the goof by
finding a solution for the disaster. Don't blame it on the UIPageViewController. It is doing
its job perfectly!
Just ask yourself - would you do the same thing with a PAGE-CURL animation? NO ?
Well, neither should you with a SCROLL animation!!! An animated page turn is a page turn and only a page turn!
In either mode!
And if you decide to tear out PAGE 2 to PAGE 7 of your BOOK that's perfectly fine!
But just don't expect UIPageViewController to invent a non-existing PAGE 7 when turning back to the recent page unless YOU tell it that things have changed...
If you really want to achieve an uncoordinated jump to elsewhere, well - do it without an
animation! In most cases this will not be very elegant but - it's possible... -
And the PVC even plays nicely along! When jumping to a new SPACE without animation
it will ask you further down the road for both - the BEFORE and AFTER controller. So your application-logic can keep up with the PVC...
But with an animation you are always conveying - move to the previous/next space (BEFORE -
AFTER). So logically there is no need at all for the PVC to ask again about a space it already
knows about when animating page turns!!!
If you wanna see PAGE 7 when flipping back to the left after having animated from PAGE 1
to the right - well, I would say - that's definitely your very own problem!
And just in case you are looking for a better solution than the 'completion-block' hack from
the accepted answer (because with it you are doing work beforehand for something that might
possibly not even get used further down the road) use the gesture recognizer delegate:
- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
Set your PVC's DataViewController here (without animation) if you really intend to go back
left to PAGE 7 and the DataSource will be asked for BEFORE and AFTER and you can submit
whatever page you like! With a flag or ivar that you should have stashed away when doing your uncontrolled
jump from PAGE 1 to 8 this should be no problem...
And when people keep on complaining about a bug in the PVC - doing 2 page turns when it is
supposed to do 1 turn only - point them to this article.
Same problem - triggering an un-animated setViewControllers: method within the transition gesture
will cause exactly the same havoc. You think you set the new center - the DataSource is asked
for the new BEFORE - AFTER dataController - you reset your index count... - Well, that seems OK...
But - after all that business the PVC ends its transition/animation and wants to know about the
next (still unknown to it) dataViewController (BEFORE or AFTER) and also triggers the DataSource. That's totally justified ! It needs to know where in its small BEFORE - CENTER - AFTER
world it is and be prepared for the next turn.
But your program-logic adds another index++ count to its logic and suddenly got 2 page turns !!!
And that is one off from where you think you are.
And YOU have to account for that! Not UIPageViewController !!!
That is exactly the point of the DataSourceProtocol only having two methods! It wants to be as generic as possible - leaving you the space and freedom to define your own logic and not being stuck with somebody else's special ideas and use-cases! The logic is completely up to you. And only because you find functions like
- (DataViewController *)viewControllerAtIndex:(NSUInteger)index storyboard:(UIStoryboard *)storyboard position:(GSPositionOfDataViewController)position;
- (NSUInteger)indexOfViewController:(DataViewController *)viewController;
in all the copy/pasted sample applications in the cloud doesn't necessarily mean that you have to eat that pre-cook food! Extend them any way you like! Just look above - in my signature you will find a 'position:' argument! I extended this to know later on if a completed page turn was a right or a left turn. Because the delegate unfortunately just tells you whether your turn completed or not! It doesn't tell you about the direction! But this sometimes matters for index-counting, depending on your application's need...
Go crazy - they are your's...
HAPPY CODING !!!

Show progress bar when sending pages to the printer (WPF)

I am creating printouts in WPF using flow documents. These printouts are set in separate window where DocumentViewer is placed.
When user clicks print I would like to show a progress bar that informs about current page that is sending to the printer. How can I do this?
I'm not sure exactly where your print code is, or where you want the progress bar, but I did something similar to this recently. This will be in VB.net.
First of all, create a new progressbar in the same class as the code you use to send the page to the printer. Then, we're going to take advantage of the "top-down" order in a block of code to change the progress bar.
The progress bar's value should be set to "0" be default. Now, in the code for sending the page to the printer, you're going to increase the progressbar's value (such as with the code "MyProgressBar.Value = MyProgressBar.Value + 1"). Put this code in between each line of the code you want to show progress for.
I would change the "+ 1" part of the code, however, to another value, so your progress bar progresses equally after each step. If you have three lines of code, then use "+ 33" (100\3), four lines use "+ 25", etc.
Finally, at the end of the code, set "MyProgressBar.Value = 100"
This only works, however, if you have access to a code longer than one line. For one line of code, I'm not sure how this works, unless you can get to the block of code that line points to.
If you have to use code from another class, you may need to do something like...
Dim MyWindowWhereProgressIs As New MyWindowWhereProgressIs
And then, each time you need to change the value, try...
MyWindowWhereProgressIs.MyProgressBar.Value = MyWindowWhereProgressIs.MyProgressBar.Value + 1
I'm not entirely sure whether or not those last two lines of code will work, as I'm away from Visual Studio right now, but it is worth a shot.

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