Under Windows their is something called a Windowless Control.
RichEdit
What is a Windowless Control and what are its benefits?
A Windowless control is an object that gives you the behavior of a control without requiring you to create a window.
This is useful when you want to modify or extend the behavior, or when you want to make use of the behavior in places where creating a window would be awkward or difficult.
Say, for instance, you want to imbed hundreds of rich edit controls on a page, if they were each windows, then each would have to get focus in order to get user input, and each would paint individually, etc.
But if you are willing to keep track of the locations of the windowless controls and do some other housekeeping that you would normally get for free by creating a window (i.e. routing keyboard messages), then you can get better results with lower overhead by using windowless controls.
This might be helpful.
Anon's right. It's a control that doesn't require an underlying window handle (HWND). The need for those arose especially with web browsers, since there's a limit of 10,000 max handles per process. You would open like two tabs of semi-complicated web pages and you'd run out of handles.
Working with and especially rolling your own windowless controls is hard, because at least you need to recreate their original, sometimes very complex and tricky implementation. (f.e.: IE's listbox is still windowed control because of all the tricky intricacies)
Windowless controls do not have a dedicated window handle.
in my opinion,windowless control might use less sys resource and it's easiser to customize
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I am experimenting with a home-grown application hosting framework, and I'd like to abstract the input/output so I can gracefully handle crashes. Chrome uses a very similar model.
Is there any way I can take an arbitrary window handle, and persuaded it to start rendering to a back-buffer? Or should I create my own window first, and then reparent the client app into it?
As the comments said you can do anything if you're willing to dig in and hook the APIs themselves, but according to the remarks in the MSDN WM_PAINT page WM_PRINT is the supported way to force a window to paint on a specific DC.
It sounds like you also need to keep the window from showing up on the desktop - in that case you can use WM_SETREDRAW as described in On Win32, can I disable painting of a window for a period of time?.
Is it usual to use a Dialog as main Windows? So without registering any user class via RegisterClassEx? Can I do everything I do via CreateWindow()? Why should I create controls such as buttons,editboxes etc via CreateWindow() instead of just making a Dialog and use it as main Window?
I'd also like to know main difference between a dialog and a windows and why use one the first instead of the second.
Thanks
Is it usual to use a Dialog as main Windows?
Yes, it is quite common.
So without registering any user class via RegisterClassEx?
A dialog is usually a predefined window class, so there usually no need for registering.
I'd also like to know main difference between a dialog and a windows and why use one the first instead of the second.
Well, two big differences would be that you cannot resize a dialog box and it has no minimize or maximize buttons (by default, but there are workarounds for this). Keep in mind the name, dialog box. In other words they are used for having a dialog with the user (receive input and displays messages to user). In a sense they are just like any other window, underneath CreateWindowxx, etc. is called, etc. However, they are somewhat predefined windows which can be made quickly and there are limitations to what you can do with them.
Also, a dialog uses a dialog procedure rather than a window procedure, which does some default processing for you, such as initializing some controls, etc.
Yes, an application can be dialog-based. There's even a Wizard for that if your'e using VisualStudio and MFC.
In VS2010, Create New Project > MFC Application. In "Application Type" select Dialog Based. Click through the rest of the Wizard, and you're off to the races.
Dialog-based applications are much simpler, architectually, than other designs such as Document/View. As such, simple things are much easier to "bang out" quickly, but the limitations of the design become apparent when you try to do more complex things. You could end up replicating much of the Doc/View architecture in your dialog-based app in order to build a production-quality Dialog-based application. In that case, did you really save yourself anything?
A dialog is a kind of window just as all of the various controls like buttons are really just windows. You can think of a dialog as being a kind of window with a lot of extra functionality to support the kinds of things that dialogs are used for.
There are two types of dialogs, modal which display and expect you to use them and then dismiss them, and non-modal which display but which do not capture and keep the input focus until they are dismissed. You can see these two types used in applications where a modal dialog is used to display an error or require the user to make some setting and a non-modal acts as a kind of tool box that stays displayed and when you need it, you click on it to do something and other times you are using some other window in the application.
Normally a dialog would not have a menu bar but would instead have all of its controls visible or easily accessible via tabs or some other type of presentation. Visual Studio and other IDEs have dialog designers to allow the placement of various controls along with wizards to allow the controls to be tied to classes and class members.
Which brings up a major difference between a dialog and a window. A window is kind of an empty page and to do things with the page requires more work. A dialog has tools that make the design easy however you are also constrained in large part by the toolbox.
If you have an application that is focused on basically allowing a user to specify certain settings and then do some task, a dialog works fairly well. If you have something that requires more complicated user interaction, an application window as the base from which all of your other dialogs and controls will be managed and manipulated will be more necessary.
I’m writing a little Windows application which has two list-view-controls. I have set it up so that the user can tab (focus) between the two, but I need a way of visually indicating which is the active control. I don’t want to go to the trouble of messing with owner-drawn controls, so I experimented with some of the different window styles like border and client edge, but none look good. I decided to toggle the disabled property because it looks best and is easy to use.
The problem now is that I have the controls set up so that whenever the user clicks on either one, it grabs the focus (calls SetFocus(), sets a handle to itself, etc.) but of course, disabled controls don’t get event notifications like mouse clicks.
Does anyone have a suggestion on how I can retain the visual distinction of the active control and also be able to toggle the active window with the mouse?
Hans’ suggestion of using CTRLCOLOR reminded me of using that a long time ago to easily make some changes to the colors of controls which then reminded me of CustomDraw.
I decided to use CustomDraw to indicate the currently active control because it is even easier, and yet provides even better control.
I have a friend who's working at a company that offers pretty poor support for its developers (scoring a 1/12 on the Joel Test).
Their build process is locked down pretty tight, and depending on the size of project it could take 40+(x2) mouse clicks to deploy. So I thought, "Hey, why not automate it the clicks using the win32api?" (Specifically using Python). I've got him a real nice tool that works just fine except for one issue - the tool that they use has a navigation pane that may or may not be open.
You can open and close it with a button press, but I'm not sure how I could make sure it was either open or closed. It's irrelevant to the build process - the only problem is that it alters where the mouse needs to click on the screen depending on its open status. The application is written in .NET and it exposes a function call that applications are able to use to toggle the panel, so I've been looking around for ideas and so far I've got two of them:
Attach to the process via a debugger and execute the function call somehow.
Take a screenshot at the location of the panels titlebar (which I've got through the win32 API and doesn't appear to change regardless if the panel is hidden or not).
Is there an easier way to figure out the state of this panel? The developers are given an admin account on their machine in addition to their regular account, so I can entertain ideas that require admin access, though I don't think that should be necessary?
UPDATE:
It looks like there's a button that can close the pane. In UIAVerify something shows up as "text" "Navigation" "btnClose". It says its AutomationId is btnClose but it's a ControlType.Text
What technology is this panel built from? Is it standard GDI or WPF? If its GDI, it should have a HWND. You should be able to find this HWND through either a class name or window title. Once you have the HWND, you can get its width.
If its built with WPF, er, I have no idea, but Snoop does this kind of thing, so I know its possible.
I want to get the window handle of some controls to do some stuff with it (requiring a handle). The controls are in a different application.
Strangely enough; I found out that many controls don't have a windows handle, like the buttons in the toolbar (?) in Windows Explorer. Just try to get a handle to the Folder/Search/(etc) buttons. It just gives me 0.
So.. first question: how come that some controls have no windows handle? Aren't all controls windows, in their hearts? (Just talking about standard controls, like I would expect them in Windows Explorer, nothing customdrawn on a pane or the like.)
Which brings me to my second question: how to work with them (like using EnableWindow) if you cannot get their handle?
Many thanks for any inputs!
EDIT (ADDITIONAL INFORMATION):
Windows Explorer is just an example. I have the problem frequently - and in a different application (the one I am really interested in, a proprietary one). I have "physical" controls (since I can get an AutomationElement of those controls), but they have no windows handle. Also, I am trying to send a message (SendMessage) to get the button state, trying to find out whether it is pushed or not (it is a standard button that seems to exhibit that behaviour only through that message - at least as far as I have seen. Also, the pushed state can last a lot longer on that button than you would expect on a standard button, though the Windows Explorer buttons show a similar behaviour, acting like button-style checkboxes, though they are (push)buttons). SendMessage requires a window handle.
Does a ToolBar in some way change the behaviour of its child elements? Taking away their window handle or something similar? (Using parent handle/control id for identification??) But then how to use functions on those controls that require a windows handle?
If they don't have a handle, they're not real controls, they're just drawn to look like controls.
But of course, the toolbar buttons in Windows Explorer do have window handles, they're part of a toolbar. Use the toolbar manipulation functions to interact with them, not EnableWindow.
Or, better yet, use the documented APIs for things like search. Reverse-engineering Windows Explorer has never ended well for anyone, least of all the poor Windows Shell team, saddled with years of backwards-compatibility hacks for certain developers who thought that APIs are for everyone else. Whatever you do manage to get to work is very likely to break on the next version of Windows.
The controls you are talking about are using the ToolbarWindow32 class. If you want to interact with them then you'll need to use the toolbar control APIs/message. For example for enabling buttons you'd want to use TB_ENABLEBUTTON.
You can implement the controls yourself using GDI, OpenGL or DirectX. Try Window Detective on Mozilla Firefox and you will see that there is only one window. Controls in dialog boxes are not windows known to Windows.