I am trying to measure UI elements but don't want to add them to the visual tree. Is there ANY way that I can do this without dispatching to the UI thread?
For example - I have some code that needs to know how big a button with the text "Foo Button" in it with a certain font size, padding, etc. The kicker is, once I know the theortical size of that Button, I don't need it anymore.
Anytime I even try to create an instance of a Button (or any UIElement for that matter) I get a thread access exception.
My guess is there's no way around this but I'm really hoping I'm wrong!
Related
I am trying to show a web page in a dialog control. All is working fine till I maximize the parent window, the inner control with webpage retains its size and so a blank area is left at the side of window. I want to know is there any WS_* message or something I can use to auto resize control when we resize the main window. I am using resource hacker so may be there can be some trick I should know.
Any help is appreciated.
Thanks.
The application must perform the resize. And it does so when it receives a WM_SIZE message for the parent control.
You are not going to be able change this by modifying the resources in a pre-existing binary. You are going to need to write some code to respond to that message.
The way I'd try seeing as I've never tried to hack something like this in.
Would be to see if the web control had an anchors property.
Its should be being passed a wm-size message, it's just not doing anything with it.
If you anchor all four corners of the webcontrol it should resize relative to it's parent.
The other way this is done is through explicit code that handles a resize event, don't think you could hack that in very easily though.
I need to change the Background Image of my Application if user changes theme from "Light" to "Dark" or vice-vesa in code behind. I hope these should be done in Page Loded event
#TimDams pointed you to one of the nice ways to detect what-theme-is-now-set, but I didn't notice there any information how to detect a change to the theme during the application runtime. The user could start your app, then bump forward to the menu, change the theme, and get back to your app. While you may think that your app will be tombstoned and then restarted and renavigated to your page with full cycle with all pageloads -- it is not 100% true.
Firstly, the PageLoaded is NOT a good place to do the initial check-and-set-styles, because, if you get that event called, then the page, probably, has already rendered once. If I remember well, the PageLoaded is invoked just after the first render. If this is true, then you will have to detect the colors earlier, for example in the LayoutUpdated (warning: this event is a great spammer. I mean, it gets called gazillions times. Attach a single-shot handler, you know, such that will instantly unattach-self on first invocation). Maybe you will be able to do it in the Page's .ctor, just after InitializeComponent. Or in the OnApplyTemplate or MeasureOverride, or at least ArrangeOverride -- the visuals should be mostly/fully available there.
Buuuut. I've intentionally 'bolded-out' the word "initial". With Mango, there's some multitasking getting more and more common, but even the pre-Mango 7.0 version does not guarantee that your app will be tombstoned. From my observations in early 7.0, for example, starting the MediaPlayer from WebBrowser component does not tombstone your app:) If you have some time to read, check WP7 recover from Tombstone and return to page for details on the "pause" vs "tombstone".
Anyways, if your app gets "paused" and the user switches themes in the meantime, I think (I've NOT checked) that your page will (in most of the cases) be just temporarily hidden and upon returning to the screen, it will probably not be re-created and will not be re-(Page)Loaded. If it is true, then you will have not so easy problem to solve, because your app may be paused, the OS rethemed, and your app unpased virtually in any moment of time and the only events you will get in the mean time are .... global events of App.Deactivated and App.Activated. It is possible that completely none of per-page events will fire [but I've not checked - before you do anything I suggest below, CHECK IT].
If this pessimistic view is really true, than in those events, you will have to detect the current theme (->Tim's post), then somehow inform your current Page that themes changed - or not. If you have your ViewModel at least a bit separated from the rest of the app (as it should be:) ) you have an easy option to do it: create in that ViewModel a set of properties (dp or inotif) like Brush Background, Brush Foreground, Brush Hightlight, and other that you need, and instead of harcoding colours in your XAML - bind to those properties. You may event want to create a separate class for all those many Brushes and other Styles, let's say "pub class MyCurrentAppTheme" and keep that props there, and expose such object from ViewModel - whatever. Just Bind your colors to whatever -- but whatever that will be "logically global" and that will be easily accessible from the App.Acticated event handler. Having that done, in the App.Activated, detect the current theme and if changed, so through all the colors kept in VM and set them appropriatelly. Voil'a, whole your App gets recoloured properly.
But mind that still - there might be some transient blinks and flashes between the rendering of cached old theme, refreshing databound objects, and redrawing fresh theme. I hope not, but I sense it may occur, especially when returning from fast-switch tool (long back press): I think that the device captures the 'last screenshot' of your app in the backbuffer and uses that throughout all the time the app is 'minimalized' to do transitions animations, to show the fast-app-switch overview and so on.. again, I've not checked, but I doubt that during such animations the pagecontents are 'live', it could be very demaning on CPU/GPU resources. Any one knows anything on that? It could be a nice test to have some looping animation on the page and then to switch out and check in the fast-switch overview, whether the animation moves or is halted!:)
If your application is tombstoned, all your controls will be recreated and the new theme will be applied. If you'd like to manage your light/dark specific styles in a similar vein to normal themes, you might want to take a look at a custom ResourceDictionary I blogged about a while back.
Unfortunately, as of Mango there, is a bug (?) related to fast application switching that causes the theme to remain unchanged in your application. The bug is outlined in this question and its linked posts:
Is there a bug when changing themes when app is deactivated and reactivated in Windows Phone Mango
My ResourceDictionary is still useful for the initial startup but it appears, unfortunately, that nothing can be done to workaround the Mango bug.
For this no event exists. You need to figure this out manually by comparing the PhoneBackgroundBrush color to see if the user has the dark or light theme and compare it with your last stored value.
Were you able to do some test on the App.Activate - Deactivate?
I decided to use a different path to solve the issue of dynamic theme change.
I've assigned to all text and buttons only system resource colors.
For the icons inside the buttons in the window instead of using PNG images-icons I used the in XAML and assing it a Foreground color from system resource.
For the buttons in the SystemMenuBar there is no issue as they are always on a dark gray background so the black PNG images work just fine.
Hoping this helps.
You can check if the dark theme is in use with this simple check:
public static bool CurrentThemeIsDark
{
get
{
return (Visibility)Application.Current.Resources["PhoneDarkThemeVisibility"] == Visibility.Visible;
}
}
To modify a window of another program, I need to find a specific SysTreeView32 in it using EnumChildWindows API call.
When I inspect the window using Spy++, there are a number of SysTreeView32's in it but all are greyed out except one, which is the one I'm looking for.
The following picture is an example of grey items:
Why are the shown items gray and what API call does Spy++ use to know whether it should grey out an item or not?
Those are just non-visible windows - ie HWNDs that don't have the WS_VISIBLE style bit set. They are often worker windows - windows that just exist to process various messages in the background - or in some cases are UI that's yet to become visible. For example, a window that lets you hide or show a toolbar may just hide it by making it invisible rather than destroying it and recreating it later.
In your specific case, the WorkerW could be a placeholder for some other piece of UI that's not needed right now, while the msctl_statusbar32 looks like it's a hidden status bar.
We have a fairly complex GUI, so when certain windows are resized their Redraw() is set to false till the operation is completed. The problem with this is that if the OS "Show window content while dragging" setting is checked, when decreasing the window's size the windows behind it are not repainted. This means I have to force the repaint myself so the remains of the resized window are deleted. I have no problem getting the dimensions of the region that was uncovered. What I'm looking for is best way to cause all windows within that region to repaint their part.
Not being much of a GUI programmer, I can traverse the uncovered region and list the windows in it. Then, I can ask each one of them to repaint its part. But I'm quite certain there has to be a better way to do this...
It is worth mentioning the app is written in PowerBuilder. This means I can call whatever Win32 function I'd like, but have limited control over the GUI behavior and the message handling. If there's a better way to prevent the window's content resize from being visible, or there's a way to make a non-redrawn window clean after itself, I'd love to hear it (just have the limitations above in mind).
I'm curious what version of PowerBuilder you are working in? I do resizing all the time and never run into issues like you are describing.
Maybe you can lay out some more detail on why you need to set your redraws to false within the PowerBuilder environment.
Hope I can help.
I am designing the (G)UI of a program, and have stumbled across a problem; The program will convert a number into different units, and the layout of a unit been converted to is:
[Unit name (when clicked gives information)]
[Special status, if any]
[Output in textfield that can also be used for input (to convert to other units)]
I want the user to be able to copy an outputnumber onto the clipboard, without having to mess around with highlighting and finding the right buttons to press. So, I thought I'd make a button after the text-output field, saying something like "C" or "Copy".
But I was reading on joelonsoftware.com yesterday, and discovered that users seem to be cursorclumsy. So what should I do?
I've thought about a number of different options:
Click on textfield to copy to clipboard - BUT: I want to use it for input as well
Pressing a numeral on the keyboard to copy the respective one - BUT: There will probably be more than 10, and I need them for new input
Bigger Copy button, like on that actually says "Copy" - Hmm, would this work? I know that I like to use the keyboard when I can, so a solution involving it would be nice.
Each unit will have its own space, where everything (name, textfield etc.) fits in. What if it would copy to clipboard when clicked anywhere in that space except for on the name or textfield. - BUT: What if you miss, meaning to click below one textfield, and clicking above another?
But what about highlighting the unit's space as I went along? - Could still mean trouble...
What do you think? I think I just might opt for #3 - Bigger copy-button..
There's nothing wrong with a Copy button after every field if you feel that it's going to be a very common operation.
Two suggestions, however:
In terms of look and feel, make sure that the button is clearly associated with the field. For a text field, the best way to do this is to put the Copy button inside the text field (on the right side - but be prepared to handle RTL languages by switching its position as needed!).
To avoid making it overly big, don't use any text, but rather use the stock Windows icon for Copy (like this one: ), and put the text into its tooltip. If you do that, you may also get rid of button border entirely, further reducing its size, though you'd still want some visual hover indicator to make it clear that it's an active UI element. In fact, you might want to specifically copy Vista/Win7 Explorer (also seen in IE7/8) UI for location field and the Reload icon in it.
I think the solution #3 is the best in your list, but I would like to see a sketch of your GUI.
What ever you do, it is important to use the OS standard keyboard and mouse event bindings and preferable look-and-feel too otherwise users get confused.
For sheer speed, the keyboard is the way to go. How about letters A-Z to copy the text boxes instead? Skip “E” to allow scientific notation to be inputted. Potential speed is high, but learnability is low. I’d expect users will have a hard time figuring out this UI even with explanatory text on the page/window, and if users have to read explanatory text, then the time that takes will likely negate the time savings of the UI, unless the user is using the app all the time (Joel also writes correctly that users hate to read).
For an app that will be used only occasionally, the big button is a better choice, the bigger the better, as predicted by Fitts’s Law. And absolutely label it “Copy,” not “C” and not an icon, to maximize learnability. Your other ideas have learnability and tolerance issues without the speed of the keyboard.
That said, I think you’re taking what Joel says too far. Certainly you want to eliminate unnecessary clicks, but the typical design for this type of app would require one click on the text box (which should by default highlight the whole value) followed by one click on a Copy menu item –or better, Alt-C or Ctrl-C from the keyboard. It’s hard for me to imagine a task where saving one click or a couple keyboard presses would be worth the clutter of a bank of Copy buttons beside your text boxes. Are you also going to have buttons for Paste and Clear? At some point the clutter will slow your users down more than the extra click.
How often are users going to be copying? If it’s really dozens of times per session, then you should re-think the whole design approach because any copying and pasting of one number at a time is going to get tedious. Maybe you should support batch processing, taking multiple numbers at once and outputting results in a form already suitable for the expected use. Maybe have it work within other apps like the way Enso does: user highlights a number in any document or text field of any app, commands Convert - Feet - Meters and it’s changed in the document or field.
If you accidentally click on the wrong area, you could just click on the right area after that. If your issue lies in the user not knowing when they click on the wrong area, just highlight the last-clicked area.
Is there a problem with copying whatever is in the textfield when they click on it? So what if it's being used for input? They're just going to copy the value they need after they type values in.
You could also have a ctrl-click or shift-click in the text box be a copy.
Most people know how to copy text on their own computer. Perhaps the best solution is to just auto-highlight all the text in a textbox when it gets focus so they can just ctrl-c to copy or start typing to begin input.