Disabling or removing the close button from uwp ap

问题:

Universal app does not allow to remove or disable the close button it seems. We can hide it by going full screen. But when moving cursor over it, brings title bar back. Is there any way to remove the close button?

Reason : I am working on screen time. After allowed time gets over, I want to block the screen. I should remove close button so that user cant get over my app.

Edit : Removing close button wont help completely. It is a part of work. I am just asking how to remove it.

回答1:

With current released API, we are able to customize the color of these three buttons in title bar. But there is no property or method could be used to disable or remove these buttons.

In UWP, we can use ApplicationView.TitleBar | titleBar property to get the title bar like following:

ApplicationViewTitleBar titleBar = Windows.UI.ViewManagement.ApplicationView.GetForCurrentView().TitleBar;

This property's type is ApplicationViewTitleBar. It only has several properties that can customize the button's color like:

titleBar.ButtonBackgroundColor = Windows.UI.Colors.White;
titleBar.ButtonForegroundColor = Windows.UI.Colors.White;
titleBar.ButtonHoverBackgroundColor = Windows.UI.Colors.White;
titleBar.ButtonHoverForegroundColor = Windows.UI.Colors.White;
titleBar.ButtonInactiveBackgroundColor = Windows.UI.Colors.White;
titleBar.ButtonInactiveForegroundColor = Windows.UI.Colors.White;
titleBar.ButtonPressedBackgroundColor = Windows.UI.Colors.White;
titleBar.ButtonPressedForegroundColor = Windows.UI.Colors.White;

Using these properties may make the close button invisible like:

However this won't actually hide these buttons. Users can still minimize or maximize the app and when the pointer is over the top right corner, they will still see the close button.

From Windows 8.1, if we want users to use only an application and do nothing else including closing the application, we can use Kiosk Mode. For more info, please see Enable Kiosk Mode in Windows 8.1 and Set up a kiosk on Windows 10 Pro, Enterprise, or Education. However this won't meet your requirement as you want to block the screen after allowed time gets over.

So UWP may not be the best choice for your requirement. You may try to implement it with classic desktop apps.

回答2:

In Windows 10 version 1703 (build 10.0.15063) and beyond, you can prevent the app from closing, using the SystemNavigationManagerPreview class.

Add this to your app manifest:

<Capabilities>
    <rescap:Capability Name="confirmAppClose" />
</Capabilities

You need to have the rescap namespace at the Package element:

xmlns:rescap="http://schemas.microsoft.com/appx/manifest/foundation/windows10/restrictedcapabilities"

In the constructor of your main form, add:

var sysNavMgr = SystemNavigationManagerPreview.GetForCurrentView();
sysNavMgr.CloseRequested += OnCloseRequested;

OnCloseRequested can be implemented as follows:

    private void OnCloseRequested(object sender, SystemNavigationCloseRequestedPreviewEventArgs e)
    {
        var deferral = e.GetDeferral();
        e.Handled = true;
        deferral.Complete();
    }