stride3d/stride · error · ArgumentNullException

coreWindow

Error message

coreWindow

What it means

InputSourceUWP's constructor requires a valid UWP CoreWindow to attach input handlers to. If the coreWindow parameter is null, the constructor immediately throws ArgumentNullException via the null-coalescing throw expression. This library fails fast because an input source without a window cannot receive any pointer or keyboard events.

Solutions

1. Ensure the CoreWindow is obtained (CoreWindow.GetForCurrentThread()) on the UI thread before constructing InputSourceUWP.
2. Guard the construction site with a null check and defer input-source creation until the window is ready.
3. Run input source setup on the main/UI thread so the current CoreWindow is resolvable.

Example fix

// before
var source = new InputSourceUWP(someWindowField);
// after
if (someWindowField == null)
    throw new InvalidOperationException("InputSourceUWP requires an initialized CoreWindow; create it on the UI thread.");
var source = new InputSourceUWP(CoreWindow.GetForCurrentThread());

if (coreWindow == null)
    throw new InvalidOperationException("InputSourceUWP requires a CoreWindow; obtain it via CoreWindow.GetForCurrentThread() on the UI thread.");
var source = new InputSourceUWP(coreWindow);

bool HasCoreWindow(Windows.UI.Core.CoreWindow w) => w != null;

try
{
    var source = new InputSourceUWP(coreWindow);
}
catch (ArgumentNullException)
{
    // Defer initialization until the UI thread provides a CoreWindow.
}

When it happens

Trigger: Calling new InputSourceUWP(null) or passing a CoreWindow field/property that has not yet been initialized when constructing the input source.

Common situations: Setting up Stride input in a UWP app before Window.Current/CoreWindow is available (e.g. in a background thread or before activation completes); refactoring code so a window field is no longer assigned before the input source is created.

Related errors

• Cannot add null instance of VirtualButton
• Cannot set null instance of VirtualButton
• uiControl
• A Gear constraint always needs two rigidbodies to be…
• ActivatedGestures collection was modified but the action…

AI-assisted analysis of stride3d/stride@96fad776d2 (2026-09-14). Data as JSON: /api/errors/9a9f6b8978f5cea1. Report an issue: GitHub.

Appendix: source

Thrown at sources/engine/Stride.Input/UWP/InputSourceUWP.cs:47

        private readonly CoreWindow coreWindow;
        private WindowsAccelerometer windowsAccelerometer;
        private WindowsCompass windowsCompass;
        private WindowsGyroscope windowsGyroscope;
        private WindowsOrientation windowsOrientation;

        private AccelerometerSensor accelerometer;
        private CompassSensor compass;
        private GyroscopeSensor gyroscope;
        private OrientationSensor orientation;
        private GravitySensor gravity;
        private UserAccelerationSensor userAcceleration;

        private PointerUWP pointer;
        private KeyboardUWP keyboard;

        public InputSourceUWP(CoreWindow coreWindow)
        {
            this.coreWindow = coreWindow ?? throw new ArgumentNullException(nameof(coreWindow));
        }

        public override void Initialize(InputManager inputManager)
        {
            var mouseCapabilities = new MouseCapabilities();
            if (mouseCapabilities.MousePresent > 0)
            {
                pointer = new MouseUWP(this, coreWindow);
                RegisterDevice(pointer);
            }

            var keyboardCapabilities = new KeyboardCapabilities();
            if (keyboardCapabilities.KeyboardPresent > 0)
            {
                keyboard = new KeyboardUWP(this, coreWindow);
                RegisterDevice(keyboard);
            }

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