On my WP7.1 app, Windows Phone Toolkit PhoneTextBox occasionally throws an exception with Message "0x8000ffff" when setting the focus on it (by tapping the PhoneTextBox). The problem is reproduced this way:
Ensure that the PhoneTextBox.IsReadOnly is set to true.
Press back button to go to the previous page.
Navigate back to the page that contains PhoneTextBox.
Tap the PhoneTextBox so that it gains focus.
I reported this problem to Windows Phone Toolkit against version 4.2012.10.30: http://phone.codeplex.com/workitem/10726
The exception is not thrown if PhoneTextBox.IsReadOnly is set to false when back button is pressed. Since false is the default value, this exception doesn't occur at all if you don't modify the value of PhoneTextBox.IsReadOnly property.
Before this is fixed in WP Toolkit, a workaround is to set the PhoneTextBox.IsReadOnly to false in OnNavigatingFrom event handler (doing it in OnNavigatedTo doesn't work).
protected override void OnNavigatingFrom(NavigatingCancelEventArgs e)
{
ProblematicPhoneTextBox.IsReadOnly = false;
base.OnNavigatingFrom(e);
}
Related
When I use the ReturnType property and set the value to "Done" nothing happens on the keyboard. I'm expecting the keyboard to close when I press done on my keyboard and nothing happens.
The issue is on Android, but on ios it works.
<Entry ReturnType="Done" />
You can refer to Customize the return key.
ReturnType, of type ReturnType, specifies the appearance of the return button.
I created a project and tried to achieve your need:
<Entry x:Name="MyEntry"
ReturnType="Done"
Completed="Entry_Completed"/>
private void Entry_Completed(object sender, EventArgs e)
{
MyEntry.Unfocus();
}
The result is that entry lost focus as expected, but the keyboard did not disappear.
I searched relevant information about this and found it (Implement pending focus management logic in Handlers). You can follow it.
It seems the Focusable logic is still not implemented yet on Maui. They have stated it will be available in upcoming Previews.
So the workaround for this issue is setting the property IsEnabled to false and immediately setting it to true on your handler:
entry.IsEnabled=false; // This removes the focus and close the keyboard
entry.IsEnabled=true; // This re-enabled the Entry for interaction
I have a Windows 10 Universal Windows Platform app with multiple pages, a main page, a list page and a details page and use the following to navigate to List page:
this.Frame.Navigate(typeof(ListPage), parameter);
When you are on the list page you can select an item which will launch a details page like so:
this.Frame.Navigate(typeof(DetailsPage), parameter);
Which works fine, the parameter is a selected Id or information then when using the Back button which on a Desktop app or Phone uses:
this.Frame.GoBack();
This always returns to the MainPage, that is when go from Main, to List to Details hitting back goes to Main, how do I get the GoBack to Go back to the previous page, it always seems to go home rather than the user expected behaviour, an ideas how to resolve this?
I’ve seen this before when you subscribe to the HardwareButtons.BackPressed event (or whatever the equivalent is in a Win10 UWP app) on a page, but then don’t unsubscribe from it. This means two event handlers get called when pressing Back, and both event handlers call Frame.GoBack().
I always subscribe to the event in the page’s NavigatedTo event, and unsubscribe in the NavigatedFrom event.
Could this be happening with your app?
If every page in your app should have the same behaviour, i.e. go back to the previous page, then subscribe to the back button event in the app class as suggested by #RoguePlanetoid in the comments:
SystemNavigationManager.GetForCurrentView().BackRequested += OnBackRequested;
The OnLaunched method would be a good place to do this. Don't forget to tell the OS to display the back button when the app is running on a desktop or tablet:
SystemNavigationManager.GetForCurrentView().AppViewBackButtonVisibility = AppViewBackButtonVisibility.Visible;
Then, add an event handler in the app class like this:
private void OnBackRequested(object sender, BackRequestedEventArgs e)
{
Frame rootFrame = Window.Current.Content as Frame;
if (rootFrame.CanGoBack)
{
e.Handled = true;
rootFrame.GoBack();
}
}
If you want different behaviour on different pages when back is pressed, i.e. ask the user to confirm losing their changes or something, then subscribe to the back button event in a pages OnNavigatedTo method (the code will be same as above), but make sure you unsubscribe in the page's OnNavigatedFrom event:
protected override void OnNavigatedFrom(NavigationEventArgs e)
{
SystemNavigationManager.GetForCurrentView().BackRequested -= this.OnBackPressed;
base.OnNavigatedFrom(e);
}
I recently added the search contract to my app. It is working great! But, whenever I search in the app when it is not running, it only starts with a blank screen. I did the part to add search results even in OnSearchActivated method. But even if I remove the code that I added, the blank screen persists. I created a blank project and added the search contract to it. And it is working in it even when the app is not running. The issue seems to be with my app only. I cannot debug it because it is something that runs when the app is not even running. Tell me a solution.
Code in OnSearchActivated and OnLaunched
Protected Overrides Async Sub OnSearchActivated(args As Windows.ApplicationModel.Activation.SearchActivatedEventArgs)
Dim previousContent As UIElement = Window.Current.Content
Dim frame As Frame = TryCast(previousContent, Frame)
If frame Is Nothing Then
frame = New Frame
Common.SuspensionManager.RegisterFrame(frame, "AppFrame")
If args.PreviousExecutionState = ApplicationExecutionState.Terminated Then
Try
Await Common.SuspensionManager.RestoreAsync()
Catch ex As Common.SuspensionManagerException
End Try
End If
End If
frame.Navigate(GetType(SearchResultsPage1), args.QueryText)
Window.Current.Content = frame
Window.Current.Activate()
End Sub
Protected Overrides Async Sub OnLaunched(args As Windows.ApplicationModel.Activation.LaunchActivatedEventArgs)
AddHandler SearchPane.GetForCurrentView.SuggestionsRequested, AddressOf OnSearchPaneSuggestionsRequested
'Contains definition of arrays ExNam, ExAbbr, ExInst, etc. removed from here to shorten the code and focus on its logic
If rootFrame Is Nothing Then
rootFrame = New Frame()
Train_Thy_Brain.Common.SuspensionManager.RegisterFrame(rootFrame, "appFrame")
If args.PreviousExecutionState = ApplicationExecutionState.Terminated Then
Await Train_Thy_Brain.Common.SuspensionManager.RestoreAsync()
End If
Window.Current.Content = rootFrame
End If
If rootFrame.Content Is Nothing Then
If Not rootFrame.Navigate(GetType(Instructions), args.Arguments) Then
Throw New Exception("Failed to create initial page")
End If
End If
Window.Current.Activate()
End Sub
'Also the namespace definitions are done at the top so they are not the issues neither.
There is a solution to debug your app : in VS2012, Right-click on your project in the Solution Explorer, then go to the Debug tab and in the Start Action section, check "Do not launch, but debug my code when it starts".
Now you can start your app from the Search Contract even if it is not running yet and debug it!
Now for your problem, I would suggest you to check whether the data is loaded before you actually search for something.
You might be hitting the search activation with empty query string. Check your search activation handler, whether you are handling the blank query text case or not?
protected override void OnSearchActivated(SearchActivatedEventArgs args)
{
// your app initialization code here.
Frame frame = (Frame)Window.Current.Content;
if (!string.IsNullOrEmpty(args.QueryText))
{
frame.Navigate(typeof(SearchResultsPage), args.QueryText);
}
else
{
// navigate to your app home page if the query text is empty.
frame.Navigate(typeof(Home), null);
}
Window.Current.Activate();
}
I have a MessageBox being shown in Application Closing/Deactivated methods in Windows Phone 7/8 application. It is used to warn the user for active timer being disabled because app is closing. The App Closing/Deactivated events are perfect for this, because putting logic in all application pages would be a killer - too many pages and paths for navigation. This works just fine - message box displays OK in WP7.
I also know for breaking changes in the API of WP8. There it is clearly stated that MessageBox.Show in Activated and Launching will cause exception.
The problem is that in WP8 the message box does not get shown on app closing. Code is executed without exception, but no message appears.
P.S. I've asked this on MS WP Dev forum but obviously no one knew.
Move the msgBox code from the app closing events and into your main page codebehind. Override the on back key press event and place your code there. This is how it was done on 7.x:
protected override void OnBackKeyPress(System.ComponentModel.CancelEventArgs e)
{
if (MessageBox.Show("Do you want to exit XXXXX?", "Application Closing", MessageBoxButton.OKCancel) == MessageBoxResult.Cancel)
{
// Cancel default navigation
e.Cancel = true;
}
}
FYI - On WP8 it looks like you have to dispatch the MsgBox Show to a new thread.
This prompts the user before the app ever actually starts to close in the event model. If the user accepts the back key press is allowed to happen, otherwise its canceled. You are not allowed to override the home button press, it must always go immediately to the home screen. You should look into background agents to persist your timer code through suspend / resume.
Register BackKeyPress event on RootFrame.
RootFrame.BackKeyPress += BackKeyPressed;
private void BackKeyPressed(object sender, CancelEventArgs e)
{
var result = (MessageBox.Show("Do you want to exit XXXXX?", "Application Closing", MessageBoxButton.OKCancel));
if (result == MessageBoxResult.Cancel)
{
// Cancel default navigation
e.Cancel = true;
}
}
I have to port some legacy code, that uses modal dialog boxes all over the place to Metro/WinRT (using C++/CX). Because these dialog boxes provide their own message loop (using DialogBoxParam()), the calling code will wait until the user has clicked a button on the message box.
I'm currently trying to write a replacement for the old message box class, that uses XAML and the popup control. To reproduce the same behavior, I have to wait in the calling thread, but also have to keep the UI responsive. I've found out, that CoreDispatcher::ProcessEvents() can be used in a loop, to keep processing events (yeah I realize that this isn't very beautiful, but I don't want to change all of our legacy code to a new threading model). However I'm running into an issue that keeps crashing my app.
Here is a minimal example that reproduces the issue (just create a XAML app and wire this to a button):
void CPPXamlTest::MainPage::Button_Click_1(Platform::Object^ sender, Windows::UI::Xaml::RoutedEventArgs^ e)
{
bool cancel = false;
auto popup = ref new Popup();
auto button = ref new Button();
button->Content = "Boom";
auto token = (button->Click += ref new RoutedEventHandler([&cancel] (Object ^, RoutedEventArgs ^) { cancel = true; }));
popup->Child = button;
popup->IsOpen = true;
while (!cancel)
{
Window::Current->Dispatcher->ProcessEvents(CoreProcessEventsOption::ProcessOneAndAllPending);
}
popup->IsOpen = false;
button->Click -= token;
}
This seems to work well for the first one or two tries of opening and closing the popup, using the two buttons. After a few tries however, the application will instantly crash deep in Windows.UI.Xaml.dll, while trying to dereference a null pointer. I can also reproduce this in C# (with practically the same code).
Does anyone have an idea, what is going on in here? Or a suggestion for an alternative approach?
If anyone is interested: I asked the same question a few days later on the MSDN forums and got a response there from a Microsoft employee:
http://social.msdn.microsoft.com/Forums/en-US/winappswithnativecode/thread/11fa65e7-90b7-41f5-9884-80064ec6e2d8/
Apparently the problem here is the nested message loop that is caused by calling ProcessEvents inside an event handler. It seems that this is not supported by WinRT, but instead of failing in a well-defined manner, this will or may cause a crash.
Alas this was the best and only answer I could find, so I ended up working around the problem, by dispatching the event handler (and a lot of other code) into another thread. I could then emulate the waiting behavior of DialogBox()/DialogBoxParam() (outside the main thread), by waiting on an event that was signaled when the user clicked/tapped a button on my XAML "dialog" popup.
A workaround that works fine for me is to replace the line:
Window::Current->Dispatcher->ProcessEvents(CoreProcessEventsOption::ProcessOneAndAllPending);
with:
auto myDispatchedHandler = ref new DispatchedHandler([&](){
Window::Current->Dispatcher->ProcessEvents(CoreProcessEventsOption::ProcessOneAndAllPending);
});
dispatcher->RunAsync(CoreDispatcherPriority::Normal,myDispatchedHandler);
For more info see this post at MSDN.