I have created a Window and then, created 50 buttons on this Window but I can only see 10 buttons on my window. Rest are out of view since I am not able to scroll the window down.
I have added auto scroll to window by adding
WS_VSCROLL | WS_HSCROLL | ES_AUTOVSCROLL | ES_AUTOHSCROLL
to Window Style parameter of CreateWindowEx function. By doing this, I can see a scroll on the window but this scroll is not movable.
What is the possible and simple solution to add a auto scroll to window in order to see all the 50 buttons in such a situation.
you will have to handle WM_VSCROLLand WM_HSCROLL messages.
You must handle the button messages of your scrollbar. You enabled the scrollbar by using WS_VSCROLL | WS_HSCROLL adn you already noted that you can see them. However using ES_AUTOVSCROLL | ES_AUTOHSCROLL doesn't magically mean that the window will scroll. These flags are for edit boxes, so they automatically scroll when characters are added. Your window doesn't recognize these.
So what you must do is to write some code in your message handler when the user clicks the buttons on the scrollbar, to move the window around on your own.
Since using WinAPI directly is not exactly easy, I would recommend to use a GUI library like wxWidgets or QT, which will reduce errors and make your life easier, as there are already a lot features implemented which you might use.
If you insist on WinAPI for whatever reason, you must probably write a lot of code on your own..
Related
I have a simple task that I want to accomplish: Have a WPF window launch with a Horizontal Alignment that is stretched to the total width of the current screen. I want to achieve a kind of custom Overlay MessageBox (I dont want to use third party controls such as MahApps), I am not using any third party references for this.
Please see what I have achieved so far (Not sure if the image will show, the link is http://imgur.com/e27DyNJ):
I have tried setting the width with a Controller object that I wrote which works, that basically sets the Width, Height, Left and Top to the width of the primary monitor. Downside is the window then pops up on the primary screen, not on the screen that is currently in use.
As far as I know, WPF doesn't have any multi-screen functions. You could PInvoke some native Multiple Display Monitor Functions, wrap them in a managed class and utilize them in that regard, though.
As a workaround, I have done the following:
var screen = System.Windows.Forms.Screen.FromRectangle(new System.Drawing.Rectangle((int)window.Left, (int)window.Top, (int)window.Width, (int)window.Height));
window.Width = screen.WorkingArea.Width;
window.Left = screen.WorkingArea.Left;
where window is the instance of my window I want to resize.
This works with the current screen the window was opened on.
Let me first decribe the symptoms of the problem. I'll then give additional facts and explain my question.
Symptoms
I have written a custom Windows control. The control paints itself in response to a WM_PAINT message. It also uses tracking tooltips (ie the tracking feature of the TOOLTIPS_CLASS common control).
When I drag the mouse over the control, the tooltip nicely follows the mouse. The problem is that it leaves a grey streak in its wake. This streak takes an observable amount of time to repaint -- as you can see from the attached image, I was able to hit PRNTSCRN and take a screenshot of it before the control had time to repaint itself.
(What is even more peculiar is that the WM_PAINT handler doesn't appear to have run even once. But note that the code that causes the tooltip to track is in WM_MOUSEMOVE, and that is obviously being perfectly responsive.)
Facts
Please assume vanilla C using Win32 libraries.
The WM_PAINT handler is actually very fast. The control has a number of features that require repainting the entire client area, and this is imperceptible to the user.
Indeed, some features run animations that repaint the whole client area at 15-24fps.
It is also decently efficient and doesn't repaint much more than the update rectangle on any given repaint.
The WM_ERASEBKGND handler does nothing and simply returns 1.
I never erase the background, I simply paint over it.
The window has the following style bits set:
ws: WS_CHILD | WS_VISIBLE
ex: WS_EX_COMPOSITED
cs: CS_DBLCLKS
The parent window is a top-level window with the following style bits set:
ws: WS_TILEDWINDOW | WS_CLIPSIBLINGS | WS_VISIBLE
ex: WS_EX_WINDOWEDGE
cs: CS_REDRAW | CS_DBLCLKS
The control's window class background brush is GetStockObject(NULL_BRUSH).
The only other way I have found to cause the same kind of "trail" is by dragging another top-level window over my control. The area that is temporarily obscured by the dragged top-level window leaves the same trail.
Giving the control's window class the CS_SAVEBITS style doesn't seem to make any difference. I still get the same perceptible trail of slow repaints.
Questions
Why am I getting the grey at all, especially if I set CS_SAVEBITS?
What can I do to make the grey go away?
Should I call UpdateWindow() each time I move the tooltip?
But this doesn't solve the issue of other top-level windows being dragged over top of my control.
Help!
Adding the WS_CLIPCHILDREN style bit to the parent window made this issue go away.
For whatever reason, when a window is partly obscured and then revealed, the OS is very generous with the WM_ERASEBKGND messages and very stingy with the WM_PAINT messages. What was happening is that the parent's WM_ERASEBKGND handler was erasing over top of my control. Adding WS_CLIPCHILDREN causes the parent window to clip its erasing.
Funnily enough, this solution worked for my control, which simply ignores the WM_ERASEBKGND message, but didn't work for standard BUTTON controls with style BS_GROUPBOX style. I expect this is because of the same generous WM_ERASEBKGND policy. The standard button control probably dutifully erases its background in handling that message and then vainly waits around for a WM_PAINT message.
Hi everyone I would like to implement an ImageViewer (like the one in Facebook for example) in a WPF application
I already have a ListBox whith my pictures, it works well. But I would like to add pop "image full size" when the user double click on one of them. (something like in FB, with a fade out of the background etc).
Currently I'm thinking of to use a Window...Do you have a better idea of what I should use ?
i would probably use a window for that as well. Then you can easily put an opacity animation when the window loads to give it the fade in and fade out effect
You could also use a Popup control.
It comes with some some built in (but very limited) animations, like fade, see PopupAnimation.
I'd try that and if it doesn't fit your needs, I second bflosabre91 oppionion and would use a separate opacity animated window.
But bear in mind that with an additional window you could have negative side effects e.g always sync the window positions correctly, handle task switches (ie. correctly hide the window in the taskbar/tasklist)
I need to display a virtually infinite scrollabe list of interactive widgets and add/remove them as necessary when new data is added or the user scrolls into an uncached area.
A TreeView (as asked about here) is no option, because, I need full Widgets as items (composed of standard widgets with multiple actions etc, but CellRenderer isn't for this)
Worse, I don't know my widgets' height in advance (not much variance though), so using a VBox might cause jumpiness.
Using the scrollbar should still feel as if the list was finite (i.e. updated only after scrolling has finished so the scrollbutton doesn't jump away from your mouse), and when resizing the window and the layout of the windows is updated, the scroll position shouldn't change too much (the focused widget should stay where it is, unless of course the focused widget was scrolled away…).
What's the best way to do this? Maybe even a library that just sends me signals when a new widget needs to be added?
Or could the ListView be coerced to do this in a not-too-nasty way? (i.e. draw on an offscreen buffer, copy that into the cell using CellRenderer, relay mouse/keyboard events to the actual widget?)
If it is a infinity list, then you should not try to achieve anything with a scrollbar - this is only meant for finite lists.
My suggestion is to use an overlay with 2 buttons
+------------+
| UP ARROW |
+------------+
| ITEM N |
| ITEM N+1 |
| ITEM N+2 |
+------------+
| DOWN ARROW |
+------------+
For the list between the buttons, you will probably have to implement a custom container widget yourself.
I suggest to buffer n (>=2) widgets/items in each direction in advance.
Not really related to custom containers, but custom widgets - a starting point
http://zetcode.com/tutorials/cairographicstutorial/customgtkwidget/
http://gnomejournal.org/article/34/writing-a-widget-using-cairo-and-gtk28
http://old.nabble.com/Custom-container-%2B-Child-type-with-interface-td26863728.html
I have question regarding the CreateWindowEx function. I have 2 windows, a main one and a popup one. I want a popup window to hide everywhere. It is currently not displayed in taskbar and it is not even visible in alt+tab menu. However it is visible on "Applications" tab in task manager. What flags do I need to use in CreateWindowEx to hide my popup window from there?
Current code:
hHistoryWindow = CreateWindowEx(WS_EX_TOOLWINDOW | WS_EX_NOACTIVATE | WS_EX_LAYERED, szAppName, L"HistoryWindow", WS_EX_TOPMOST | WS_POPUP, WIDTH, TOP, width, height, NULL, NULL, hInstance, NULL);
I also wanted to ask, whether I need to release a bitmap resource from "static" window before using DestroyWindow() function? I set image to a "static" window this way:
SendMessage (hStatic, STM_SETIMAGE, (WPARAM)IMAGE_BITMAP, (LPARAM)hWhiteStone);
Is it enough to release hWhiteStone or do I need to release also handle returned by SendMessage() (- or is it done automatically by DestroyWindow)?
Thank you for any info.
Kra
Make it a child of your main window. Do this by changing the fourth last parameter to the HWND of your main window. This SHOULD make windows treat your popup window as part of the same application as your main window.