I have a strange problem that disabling a Form reacts different in two different release version of our application.
In the most recent one, when disabling a Form, you cannot give it focus. When I click on a disabled form, you can hear a bell sound. No OnActivated event is triggered.
In a previous version however, disabling the same Form doesn't prevent me from giving it focus (from selecting it). As a result, the OnActivated event is triggered.
First of all, what should be normal behavior? I am not doing anything in code to prevent a Form from being activated or getting focus, so I guess the Windows Form framework executes some logic when a Form is disabled.
Second, what could cause the difference?
Related
I have a legacy application that uses Win32 (not MFC) to create graphical screens. One of the control types we use is a combo box with the droplist style (using the new Common Controls module). We have discovered a very strange thing about this control lately.
If I start the application with a mouse click, the focus indicator on the droplist does not show! This can be done using the Start->Run dialog (click OK after filling in the program to run). This can be done using a desktop shortcut (double-click). This can be done by clicking the Go button in Visual Studio 2010 to debug the program. Our user discovered this by using a small Delphi app that acts similar to Start->Run (fill in an entry field of a program to execute, and press a Launch button). If you click the Launch button, the focus indicator is missing.
If I start the application with a keypress, the focus indicator shows! Again, Start->Run dialog (but press Enter to activate the OK button). Desktop shortcut (single click to highlight the icon, then press Enter to activate it). F5 from within Visual Studio. Even the Delphi app - if you tab to the Launch button, and press Space or Enter, our application starts and shows the focus indicator on the drop list.
I have tried to create a small MFC application with just a drop list, and have started that application in all the ways described above. However, this small application always shows the focus indicator of the drop list, regardless of how I start it.
I have examined the styles of both drop lists (on my small application, as well as my actual application). They are slightly different, but changing the style of my small MFC app to match my desktop app doesn't change the behavior. Nor does changing my desktop app to match the style of the small MFC app change the behavior of my desktop app.
I modified my desktop application to require the user to press Enter after the main window is displayed, but before any graphical controls are shown. This causes the focus indicator to now show!
I have found that, when debugging my desktop app, if I set a breakpoint after the main window is shown, but before any controls are drawn, and then press F5 to continue, the focus indicator now shows. But if I click the Go button instead, the focus indicator does not show.
It seems like interacting with the keyboard somehow causes the focus indicator to show.
Note that a drop list combo box looks like a push button with a small down-arrow on the right hand side. The focus indicator is a dashed line near the inside border of the button.
I have struggled with this issue for two days now, with no indication that I am getting closer to an answer. So any insight into what may be causing this will be much appreciated.
The first comment to the question provided a partial answer. Changing the Control Panel setting for keyboard accelerators also causes the focus indicator to show, regardless of how the application is started. However, I believe this is only a partial answer.
When the CP setting is off, keyboard accelerators are supposed to show once you have pressed the Alt key. My understand, based on the blog post that Jonathon Potter linked to, is that focus indicators should show up once the keyboard is used. Entering text into an entry field probably doesn't count as "using the keyboard", but I would expect tabbing between controls to count as such.
Also, if the CP setting is off, the behavior of my application is different, depending on whether I start the application with a mouse click or a key press.
In summary, I find the behavior inconsistent. Perhaps it is correct. I find it hard to say.
I'm making a Sketchflow WP7 application which is working fine, except Navigation is sometimes buggy. Sometimes when I go to a screen and try and click it doesn't work, some times it does. I'm using the MouseLeftButtonDown Event to trigger it. After it 'freezes' I can no longer navigate via the map either, though before it freezes I can. I'm not sure if any errors are thrown because I'm not aware of a real time silverlight console. Sketchflow doesn't have a 'Debug Project' option only a 'Run Project' one.
It's very unpredictable, sometimes it works, sometimes it doesn't (though some links are more unreliable than others). Sometimes it gets stuck in different screens. I've tested this across browsers and computers and while sometimes a new browser occasionally has a better success rate, something always gets stuck.
I'm afraid I'm probably leaving out some details so feel free to ask for them. I'm not really very familiar with Silverlight and Sketchflow, I'm just working on a prototype so it seems like I shouldn't have to deal with any code based issues...
Thanks!
You might want to look for a Click Event rather than MouseButtonDown as that could be anything, it doesnt mean MouseButton Down, MouseButton Up, which resembles a click. this is just the same as if you use your finger to touch the screen, this would also trigger the MouseButton Down Eventhandler
so if I was you try and use the Click eventhandler for your navigation.
You can open the same project in VS (including the free express editions) and run it in the debugger from there to see if an exception is being thrown. That might help narrow down the problem.
I'm somewhat new to WPF and VB.Net (but not new to programming in general) and I was wondering if someone could help me with an issue that I'm having.
Here's the problem:
I am creating a simple form using WPF in VB.Net and I have a button that I want to disable or enable based on an update to a DataGrid that is located in the form. When I first show the form the button is enabled by default and everything is fine. When the DataGrid changes I can disable the button programmatically by doing btnTest.IsEnabled=False and the button grays out appropriately. However, when I subsequently call btnTest.IsEnabled=True the button becomes enabled all except for the text that is displayed on the button; that text remains grayed out. I can switch back and forth between enabled and disabled several times and the behavior described still manifests. I'm not sure if I'm missing something but this seems to be a really simple problem to me and I've wasted a few hours on it already.
Does anyone know what's going on? I've already googled everything I know.
Thanks
Tom
Just to update this: I actually found out that this was a bug in the BureauBlue theme that ships with .NET. If you have this problem tag me in a comment here and I can send you my modified BureauBlue.xaml file.
When I have 2 apps open and one has the focus but I want to execute a command in the other app, it requires a click to regain focus and another to execute the command. Is there some good reason why I couldn't take focus on MouseOver? I'm working with a WPF app if that is pertinent. TIA
EDIT: Oddly enough the MouseOvers work without focus.
I would not recommend doing this. This is not a standard way of working in Windows, so you will confuse your users. People are used to clicking into an application (or tabbing) to provide focus.
However, this is a configurable setting via the Accessability Tools in Windows. It can be enabled by choosing "Activate a window by hovering over it with the mouse" globally. Let your users specify this behavior if they want it.
The setting is configurable at a system-wide level. You should never ever override the user's current setting regarding this.
MS Windows Vista -- focus follows mouse (There's also a link on how to do it on XP.)
Edit: Normally, you can click a button on a form and both bring focus to the window and click it at the same time. The origins of the current setting "eating" the initial mouse click that brings focus to a window started as a fix to a bug in the Ribbon UI. The discussion is somewhere in this video: The Story of the Ribbon. Sorry I can't narrow it down more than that, but at least the video is a great insight and work watching - maybe you can send a message to Jensen Harris if you need a faster answer.
Edit 2: I just added a button to a WPF window, and I'm able to click it as long as I can see it - whether or not the window has focus.
You can take focus on MouseOver manually
I've been working on injecting input into a WPF application. What makes this project hard is that I need to be able to inject the input into the application even though it's running in the background (i.e. another application has the input focus). Using the SendInput() function is therefore out of the question.
So far, I've got keyboard input working but am having trouble injecting mouse input.
I used Spy++ to observe the window messages that get sent to the WPF window when I physically click the mouse button. I then simply craft these same mouse messages (such as WM_LBUTTONDOWN and WM_LBUTTONUP) manually and send them explicitly to the WPF window to emulate mouse input.
Unfortunately, this doesn't work as expected (not even when I, for testing purposes, have set the WPF window as the foreground window).
I've added a button to my test WPF window which when clicked displays a message box. Injecting the appropriate mouse messages when I've manually positioned the cursor over the button doesn't cause the button to be clicked, however (i.e. the clicked event isn't fired by the WPF framework).
If I add a handler for mouse clicks on the actual dialog (the client area), that handler does get called if I position the cursor over the dialog itself and inject the same window messages as before:
this.MouseLeftButtonDown += WndMouseDown;
public void WndMouseDown(object sender, EventArgs e)
{
...
}
Strangely enough, if I change the push mode of the button to Press (i.e. it's considered clicked on mouse down rather than the default mouse up), the button clicked event is now fired when I inject the same messages as before. (It's worth mentioning that the handler from the example above correctly fires for both mouse downs and ups, so it'd seem the WPF framework does process both messages successfully.)
It seems like there are some other criteria that need to be fulfilled in order for a mouse clicked event to be fired by the WPF framework. Does anybody know how mouse input is handled internally in WPF, or why it's not interpreting my mouse up and down messages as a click on the button?
(It's worth mentioning that this approach [sending window messages] works fine on ordinary Win32 windows, such as the Start->Run dialog. The difference here is that WPF only has one physical Win32 window and the rest is WPF specific, which means all window messages go to that top-level window rather than the actual button.)
I've been searching high and low for an answer to this and would appreciate any thoughts or ideas.
I'd highly suggest going the UIAutomation route. You create an AutomationElement by window handle. Crawl to the button and invoke it. I'd just like to know how you managed to get the keyboard input working. I am currently trying to resolve the converse issue. How to get a WPF window (I've managed to get a hWnd to it via Win32 calls), to respond to virtual keyboard messages. I've logged ++spy sessions on the window in question and replicated it's input without success.
Use UI Automation to do this - trying to manually simulate input via window messages is a textbook mistake, like trying to start a land war against Russia.
Your strategy is basically sound but in order to send a message to a window owned by another process you must first register the message.
Here is an article explaining the whole business. The sample code is unfortunately in VB but I'm sure that won't stop you.