I have an app which plays a few short sound clips. To play them I simply set the source to the new clip path, which is a WMA I encoded with Expression Encoder using WP7 settings. It's not even worth sharing the code -- there's an event handler. In it, I set the ME.Source property to a new Uri. It's set to AutoPlay, so that's it! Here:
private void PlaySound(ItemViewModel sound) {
Model.CurrentSound = sound;
CurrentSound.Source = new Uri(sound.Path, UriKind.Relative);
}
private void Sounds_SelectionChanged(object sender, SelectionChangedEventArgs e) {
var list = ((ListBox) sender);
var item = (ItemViewModel) list.SelectedItem;
SelectItem(item);
}
Also I should point out that the sounds are all resources (build type = Resource). I need them to be because the app needs to discover them dynamically. The paths are all like this, "sounds/foo/bar/sound.wma". Sometimes there is a space in the path, it is url encoded with %20 (this is how the resource manager returns the path, I didn't do that).
The problem is many people, but not all, are saying that the sound auto-repeats. The sounds are very short, only a few seconds, so it's very annoying. I don't understand how this is happening, the MediaElement doesn't even have an auto repeat feature.
Perhaps related, but some have also complained that every now and then the sound does not play. They have to click it again. All I can think of is that there is something wrong with how the sounds are encoded, but they are WMA, and as I said, I encoded them using the 'playback in WP7' settings in expression encoder. How could it be that it works usually but not other times if that were the case, anyway?
I'm at a loss and my app is getting some bad reviews because of this behavior. Help!
"there's and event handler" but you don't say of what? It could be that event firing over and over or not at all in some cases. Potentially your code has a logical errors where you have failed to detach an existing handler and then added another. As usage progresses you end up with a single event being handled by multiple handlers.
Edit
The Selection changed event is notorious for firing more frequently than we'd like. I suggest you add some debounce code that makes record of the last item selected and how long ago. If the next selected item is the same as the last one and it was say less than a second ago then swallow the event without doing anything else.
It sounds like you might be trying to play Sound Effects - in which case you might be better off using the XNA SoundEffect mechanism
e.g. http://www.japf.fr/2010/08/sound-effect-in-wp7-sl-application/
SoundEffect only works for WAV files (PCM) - but I've used it in several apps and scripts including embedded content files and downloaded files (e.g. translation and ironruby scripts).
The XNA class works well within SL and allows multiple sound effects to be played at the same time.
The problem with repeating turned out to be needing to do this:
MediaPlayer.IsRepeating = false;
I think what happened was the user would be in another app that sets this to true, and upon opening my app that value was still true! That has to be a bug, it's totally unexpected. If you look at other sound-playing apps like soundboard apps, there are users complaining in the reviews about the very same thing.. "I wish it wouldn't repeat the sounds..."
Related
i have a wpf application with login window before displaying the mainwindow.
i use mef to load all modules/parts. before the mainwindow start i check the user login data against the parts which i display then. the parts a Shared and NonShared.
[ImportMany]
private IEnumerable<Lazy<IComponent, IComponentMetadata>> _components;
[ImportMany("Resourcen", typeof(ResourceDictionary))]
private IEnumerable<ResourceDictionary> _importResourcen;
var catalog = new AggregateCatalog();
catalog.Catalogs.Add(new AssemblyCatalog(Assembly.GetExecutingAssembly()));
catalog.Catalogs.Add(new DirectoryCatalog(AppDomain.CurrentDomain.BaseDirectory));
_mefcontainer = new CompositionContainer(catalog);
_mefcontainer.ComposeParts(somepartwithaSharedExport, this);
this all works fine. but now i tried the "relogin".
_mefcontainer.Dispose();
_mefcontainer = null;
//here the stuff that works from above
first i thought it works, but it seems that the parts i create the first time still exist in memory and i have no chance to "kill" them. so i got OutOfMemory Exception when i relogin enough times.
that why i use this approach now
System.Diagnostics.Process.Start(Application.ResourceAssembly.Location);
App.ShutDown();
i dont feel happy with this.
is there a way to cleanup the Compositioncontainer and create a new one?
You could try to call _mefcontainer.RemovePart(somepartwithaSharedExport). More details here: http://mef.codeplex.com/wikipage?title=Parts%20Lifetime
For the non-shared part you can call CompositionContainer.ReleaseExport:
_mefcontainer.ReleaseExport(nonSharedExport);
For more info have a try the sample code from this answer.
As far as I know, the shared parts cannot be released without disposing the container. If you go with that path, then you will also have to make sure that no references to these objects are kept to allow for the GC to collect them. The documentation reference from mrtig's answer provides a lot of useful details concerning the lifetime of parts and you should probably study it along with the answer by weshaggard to a similar question. It also explains what happens to disposable parts.
I wrote a large complex C program around 20(!) years go. As far as I can recall it worked fine at the time in all respects - it was probably running on windows 95.
Now I need to use it again. Unfortunately the radio buttons in it do not appear to work properly any more (the ordinary push buttons are all behaving correctly). As I click on the radio buttons, I get some feedback that windows is acknowledging my click in as much as I see a dotted line appear around the button's text and the circle of the button goes grey for as long as my finger is on the button, but when I take my finger off I see that the selected button has not changed.
My suspicion is that I was perhaps getting away with some bad practice at the time which worked with windows 95 but no longer works on newer versions of windows, but I'm struggling work out what I did wrong. Any ideas?
EDIT: Its difficult to extract the relevant code because the message handling in this program was a tangled nightmare. Many buttons were created programatically at runtime and there were different message loops working when the program was in different modes of operation. The program was a customisable environment for running certain types of experiment. It even had its own built-in interpreted language! So I'm not expecting an answer like "you should have a comma instead of a semicolon at line 47", but perhaps something more like "I observed similar symptoms once in my program and it turned out to be ..... " .. or perhaps "the fact that the dotted rectangle is appearing means that process AAA has happened, but maybe step BBB has gone wrong".
EDIT: I've managed to extract some key code which my contain an error...
char *process_messages_one_at_a_time()
{
MSG msg;
int temp;
temp = PeekMessage(&msg,winh,0,0,PM_NOREMOVE);
if (temp)
{
GetMessage (&msg, NULL, 0, 0);
if (msg.message == WM_LBUTTONUP)
{
mouse_just_released_somewhere = TRUE;
}
TranslateMessage (&msg);
DispatchMessage (&msg);
}
if (button_command_waiting)
{
button_command_waiting = FALSE;
return (button_command_string);
}
else
{
return (NULL);
}
}
There are two simple things to check when using radio buttons. First is to make sure that each has the BS_AUTORADIOBUTTON property set. The second is to make sure that the first button in the tab order and the next control after the set of buttons (typically a group box) have the WS_GROUP property set, while the other buttons have it clear.
A few suggestions:
I'd try to use spy++ to monitor the messages in that dialog box, particularly to and from the radiobutton controls. I wonder if you'll see a BM_SETCHECK that your program is sending (ie, somewhere you're unchecking the button programatically).
Any chance your code ever checks the Windows version number? I've been burned a few times with an == where I should have used a >= to ensure version checking compatibility.
Do you sub-class any controls? I don't remember, but it seems to me there were a few ways sub-classing could go wrong (and the effects weren't immediately noticeable until newer versions of Windows rolled in).
Owner-drawing the control? It's really easy to for the owner-draw to not work with newer Windows GUI styles.
Working with old code like that, the memories come back to me in bits and pieces, rather than a flood, so it usually takes some time before it dawns on me what I was doing back then.
If you just want to get the program running to use it, might I suggest "compatibility mode".
http://www.howtogeek.com/howto/windows-vista/using-windows-vista-compatibility-mode/
However, if you have a larger, expected useful life of the software, you might want to consider rewriting it. Rewriting it is not anywhere near the complexity or work of the initial write because of a few factors:
Developing the requirements of a program is a substantial part of the required work in making a software package (the requirements are already done)
A lot of the code is already written and only parts may need to be slightly refactored in order to be updated
New library components may be more stable alternatives to parts of the existing codebase
You'll learn how to write current applications with current library facilities
You'll have an opportunity to comment or just generally refactor and cleanup the code (thus making it more maintainable for the anticipated, extended life)
The codebase will be more maintainable/compatible going forward for additional changes in both requirements and operating systems (both because it's updated and because you've had the opportunity to re-understand the entire codebase)
Hope that helps...
First, thanks for reading this thread and provide your suggestion.
Here’s the detailed description of my question: Due to large scale of legacy code, we need to use Win32 messages. And for UI part, we need to use WPF to modernize our appearance. That part of UI need to direct keyboard messages into the old legacy component. For input messages without IME, we have used ComponentDispatcher.ThreadFilterMessage to get these messages like WM_KEYDOWN, WM_CHAR, ect. But for IME input, we can’t get the corresponding WM_IME_* messages. Do we have a way to get these messages, or at least, get all the input text which corresponds to WM_IME_* messages?
We have tried several ways for that:
First, WPF native methods, like OnPreviewKeyDown(), OnTextInput(). One lackage of that solution is that we can’t get the Win32 messages. And I’ve found that WPF will not respond for some special key, e.g. Space key will not cause OnTextInput() to be invoked.
Second, different hooks, like SetWindowLong(), HwndSource.AddHook(). These solutions will not get the WM_IME_* messages as well.
Third, use InputMethod class. I’ve tried to use InputMethod.ImeConversionMode to determine whether the user input corresponds to WM_IME_* messages. But you know it is a different way with ComponentDispatcher.ThreadFilterMessage, and against several basic laws. At the same time, I’m not sure whether there may be cases overlapped for these two ways, and whether there’re missed cases. There’re so many languages and so many kinds of input methods, each of them has different character set and punctuation (They can be combined separately), then that solution will be risky.
When I’m investigating with class ImmComposition, which can be created by TextBoxBase.OnGotKeyboardFocus(), I’ve seen the hook ImmCompositionFilterMessage() is dealing with WM_IME_CHAR(0x0286), but failed to get it in my hook added after base. OnGotKeyboardFocus():
public class HookedTextBox : TextBox
{
protected override void OnGotKeyboardFocus(KeyboardFocusChangedEventArgs e)
{
base.OnGotKeyboardFocus(e);
InstallHook();
}
}
I am creating a xps document as below.
Assembly assembly = Assembly.GetExecutingAssembly();
//read embedded xpsDocument file
Stream helpStream = assembly.GetManifestResourceStream(resourceNameOfContext);
if (helpStream != null)
{
Package package = Package.Open(helpStream);
string inMemoryPackageName = "memorystream://" + topicName + ".xps";
Uri packageUri = new Uri(inMemoryPackageName);
//Add package to PackageStore
PackageStore.AddPackage(packageUri, package);
docXps = new XpsDocument(package, CompressionOption.Maximum, inMemoryPackageName);
}
return docXps;
When i am trying to get docXps.GetFixedDocumentSequence();
I am getting the above error. Can anyone help?
Thanks,
Your problem has nothing to do with the code surrounding the creation or use of the XPS document. It has everything to do with what thread you are running under.
You will receive the The calling thread must be STA, because many UI components require this error whenever any of the following are attempted on a MTA thread:
You construct any object derived from FrameworkElement (including Controls and Panels)
You construct any object derived from BitmapEffect
You construct any object derived from TextComposition
You construct any object derived from HwndSource
You access the current InputManager
You access the primary KeyboardDevice, StylusDevice, or TabletDevice
You attempt to change the focus on a FrameworkContentElement
You provide mouse, keyboard or IME input to any control that accepts text input
You make WPF content visible or update its layout
You manipulate the visual tree in such a way as to cause a re-evaluation for rendering
Several other changes, mostly having to do with display and input
For example, I received this error last year when I tried to deserialize some XAML that contained <Button> and other WPF objects from within a WCF service. The problem was simple to solve: I just switch to a STA thread to do the processing.
Obviously most work with XPS documents will trigger one or more of the above conditions. In your case I suspect that GetFixedDocumentSequence ends up using TextComposition or one of its subclasses.
No doubt the my solution of switching to a STA thread will also work for you, but first you need to figure out how your code that works with XpsDocuments is getting executed run from a MTA thread. Normally any code from from the GUI (eg a button press) is automatically run in a STA thread.
Is it possible that your code that manipulates XPS Documents may be being executed without a GUI? From a user-created thread? From a WCF service or a web service? From an ASPX page? Track that down and you'll probably find your solution.
If that doesn't work, let us know the details of the path through which GetFixedDocumentSequence is called, so we can diagnose it. The directly surrounding code isn't nearly as important as the call stack and how it is originally being invoked. If it is hard to explain you probably should add a call stack to prevent misunderstandings and help us diagnose the problem further, or tell you how to start a STA thread in your particular situation.
Is your code trying to access the xps doc from a background thread? If this is the case, you'll want to use the dispatcher. Info on that here.
If this doesn't help, could you post the code where you're actually calling GetFixedDocumentSequence()?
I'm attempting to use a large number of short sound samples in a game I'm creating in Silverlight 2. The samples are less than 2 seconds long.
I would prefer to load all the audio samples onto the canvas during the initualization. I have been adding the media element to the canvas and a generic list to manage it. So far, it appears to work.
When I play the sample the first time, it plays perfectly. If it has finished playing and I want to re-use the same element, it cuts off the first part of the sound. To play the sample again, I stop and play the media element.
Is there another method I should use the samples so that the audio is not clipped and good performance is obtained?
Also, it's probably a good idea to make sure that all of your audio samples are brought down to the client side initially. Depending on how you set it up, it's possible that the MediaElements are using their progressive download functionality to get the media files from the server. While there's nothing wrong with this per se (browser caching should be helping you out after the initial download), it does mean that you have to deal with the browser cache, and there are some potential issues there.
Possible steps to try:
Mark your audio files as "Content". This will get them balled up in the .xap.
Load your audio files into MemoryStreams (see Application.GetResourceStream method) and call MediaElement.SetSource().
HTH,
Erik
Some comments:
From MSDN:
Try to limit the number of MediaElement objects you have in your application at once. If you have over one hundred MediaElement objects in your application tree, regardless of whether they are playing concurrently or not, MediaFailed events may be raised. The way to work around this is to add MediaElement objects to the tree as they are needed and remove them when they are not.
You could try to seek to the start of the sample to reset the point currently being played before re-using it with:
mediaelement.Position = new TimeSpan();
See also MSDNs MediaElement.Position.
One techique you can use, although I'm not sure how well it will work in Silverlight, is create one large file with all of your samples joined together (probably with a half-second or so of silence between each). Figure out the timecode for each sample and seek the media element to that position and play. You'll only need as many media elements as simultaneous sounds you want to play.