My problem is that I have a list. When I long press a particular item in the list then it opens a context menu and when I click on a menu item inside context menu then it opens a popup,so on pressing the hardware back button i want that i again go back to the list.
so for doing this my code is:
protected override void OnBackKeyPress(object sender,System.ComponentModel.CancelEventArgs e)
{
if (calendarDescripton.Visibility == Visibility.Visible)
{
calendarDescripton.Visibility = Visibility.Collapsed;
e.Cancel = true;
}
}
After using this code when I click the button that opens the list,the application exits,it does not open list also.
I think first the Navigation should be canceled, before making any other changes. Try this
protected override void OnBackKeyPress(object sender,System.ComponentModel.CancelEventArgs e)
{
if (calendarDescripton.Visibility == Visibility.Visible)
{
e.Cancel = true;
calendarDescripton.Visibility = Visibility.Collapsed;
}
}
If this doesn't help, place a break piont at the if condition and check if it is entering inside the if or not
If the break point doesn't hit, means there is something wrong with your Navigation approach.
If you are using NavigationService.Navigate() method for page navigation, it should work.
Otherwise, if you are using,
App.Current.RootVisual = new MyPage();, then BackKey cannot be overridden.
Related
I am building an application that minimizes to tray when the user clicks the close button (the cross on the upper right corner) using this code:
private void FrmTest_FormClosing(object sender, FormClosingEventArgs e) {
e.Cancel = true;
WindowState = FormWindowState.Minimized;
}
however, if I want to actually close the window on a button using Close() this handler is called and the form doesn't close.
How can I close my form / application now?
I fixed it (thought I checked this, but apparently, something went amiss while debugging).
You can use the CloseReason property to find out why the event is called. When the user clicks on the close button on the window, e.CloseReason is UserClosing, otherwise it is ApplicationExitCall:
private void FrmTest_FormClosing(object sender, FormClosingEventArgs e) {
if (e.CloseReason == CloseReason.UserClosing) {
e.Cancel = true;
WindowState = FormWindowState.Minimized;
}
}
Update when using Close() to close the form, the CloseReason will be the same and you should use a boolean as Hans Passant mentions in the comments. When using Application.Exit(), this CloseReason solution works.
I have a main page with some options. One of them is to navigate to page 1 where there are two arrows. One that navigates to page2, page3, and the other arrow page3, page2, page1 like a loop. There is also an arrow that navigates to main page.
I want to ask if there is a way when the user presses the back button to terminate the app from whatever page the user is currently at and not to navigate through all pages.
edit
if i want when i press the back to always navigate to the mainpage what i have to do ?
clear the back stack inside the onbackkeypress function where you want to exit the app. And it will exit the app normally.
[Updated]
1) after clearing back stack. Use NavigationService.Navigate(new Uri("MainPage.xaml",UriKind.Relative)); to traverse to mainpage and do e.Cancel = true in the next statement.
2) Or clear the back stack upto the mainpage. and automatically the back press will take you to the mainpage. inside the mainpage clear the back stack fully inside the OnNavigatedTo function so that the first item is always your mainpage and user can exit easily.
protected override void OnBackKeyPress(System.ComponentModel.CancelEventArgs e)
{
while (NavigationService.CanGoBack)
NavigationService.RemoveBackEntry();
e.Cancel = true;
return;
}
protected override void OnBackKeyPress(System.ComponentModel.CancelEventArgs e)
{
while (NavigationService.CanGoBack)
NavigationService.RemoveBackEntry();
}
Throw an exception in OnBackKeyPress which terminates the app.
protected override void OnBackKeyPress(System.ComponentModel.CancelEventArgs e)
{
throw an exception();
}
You can also do like this,
check
e.NavigationMode == System.Windows.Navigation.NavigationMode.Back
in OnNavigatedTo event (you need to override this every page) and call
NavigationService.GoBack();
there is no direct way of exiting an app.. see here
hope this will work. If its XNA
if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
this.Exit();
currently I'm developing an app for WP7 but came across a little problem with a Listbox event call Selection_Change. The problem is that when i return to the page that contains the listbox the selection_change event triggers without being changed at all or without any user input. The listbox code is similar to this:
private void lsbHistory_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
int index = lsbHistory.SelectedIndex;
NavigationService.Navigate(new Uri("/Views/NextPage, UriKind.Relative));
}
On the page I navigate to, the only way out of the navigated page is by pressing back button or start button meaning that it will return to the page that contains the listbox. When I Navigate back the selection change triggers leading me sometimes to a exception. Has anyone been through this before?
Consider always checking if it's -1 (the default value).
private void lsbHistory_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
int index = lsbHistory.SelectedIndex;
if (index != -1)
{
NavigationService.Navigate(new Uri("/Views/NextPage, UriKind.Relative));
lsbHistory.SelectedIndex = -1; // Set it to -1, to enable re-selection.
}
}
Also, you should consider wrapping the Navigate call in Dispatcher.BeginInvoke to have a better, more smooth, page transition.
The event will be fired when the list is populated.
The simplest solution for you will probably be to add a check that there is nothing selected before triggering your navigation:
if (lsbHistory.SelectedIndex > -1)
{
// do navigation
}
One thing to notice is that when you navigate back to the page which containt the ListBox, the ListBox still has the SelectedItem set to the value it had when the user navigated away. This means that lsbHistory.SelectedIndex will get the index of the item which was selected when the user navigated forward.
Maybe there's something in your code which presumes that the ListBox's SelectedItem is null when the user navigates to the page?
I am working on an app on wp7.
I hope to prompt a confirmation dialog when user exit app (press back button).
Is it possible?
Welcome any comment
Please handle the BackKeyPress button in the Application page to handle the back key press.
In Page.xaml file in the element add this code
BackKeyPress="PhoneApplicationPage_BackKeyPress"
it should look like
<phone:PhoneApplicationPage BackKeyPress="PhoneApplicationPage_BackKeyPress"
..//other attributes .. >
in event handler you write the code as follows
private void PhoneApplicationPage_BackKeyPress(object sender, System.ComponentModel.CancelEventArgs e)
{
MessageBoxResult mb = MessageBox.Show("You want exit the page", "Alert", MessageBoxButton.OKCancel);
if( mb != MessageBoxResult.OK)
{
e.Cancel = true;
}
}
It's possible to catch when the user exits pressing the Back button, but it is not possible to stop the application from being made "dormant" when the user presses the hardware Start button or Search buttons.
You can stop back navigation by set e.Cancel in back key press event.
In MainPage.xaml.cs constructor:
OnBackKeyPress += (s, e) =>
{
if (MessageBox.Show("", "", MessageBoxButtons.OkCancel) == MessageBoxButtons.Cancel)
{
e.Cancel = true;
};
};
I have an application, the main page contains few functions. To explain in detail - I have save, color palette button in my main page. When any of these buttons are clicked, save pop up or color palette appears. How to handle back button of the device, when color palette or save pop up is opened. When back button is pressed at these scenario it should just make them invisible and stay on the main page. When nothing is being performed in the main page, then it should come out of the app. I tried to make their visibility collapsed on back button press. But it still is coming out of the application.
Please, guide me in this. Thanks in advance.
Override PhoneApplicationPage.OnBackKeyPress and then set CancelEventArgs.Cancel to true if you want to stop it from actually going back.
protected override void OnBackKeyPress(CancelEventArgs args)
{
if (PanelIsShowing)
{
HidePanel();
args.Cancel = true;
}
}
The back button behaves as is intended by Microsoft.
If you change its behavior you risk your application not being certified for the Marketplace.
If you want the back button to close the popups, turn the popups into pages so the back button navigates back to the main page..
You need to use
protected override void OnBackKeyPress(CancelEventArgs e)
{
if (_popup.IsOpen)
{
_popup.IsOpen= false;
e.Cancel = true;
}
else
{
base.OnBackKeyPress(e);
}
}
That should do the trick.