Access keyboard and mouse state like in WPF

[mcmikecreations]

Hi! I'm currently trying to translate code from WPF to Avalonia and I ran into problems with WPF Keyboard and Mouse classes.
I'm looking for a replacement for Keyboard.Modifiers and Mouse.LeftButton etc. for methods that are not direct mouse and keyboard event handlers. For example, this line for keyboard and this line for mouse.

P.S. As a follow-up to #5470, is there a way to access system properties like in WPF:

1. VerticalScrollBar.Track here
2. SystemParameters.WheelScrollLines here
3. Visual.TransformToAncestor here
   Maybe Point point = TransformToAncestor(_parent).Transform(new Point(0, 0)) is identical to Point point = new Point(0, 0).Transform(this.TransformToVisual(_parent))?
4. Is WPF FrameworkElement.LayoutTransform the same as Avalonia Visual.RenderTransform as here?

[jp2masa]

1. I think there's no concept of "track". The Value, Maximum and Minimum are properties of the ScrollBar (derived from RangeBase).
2. AFAIK that's not currently possible.
3. I think that's equivalent to Matrix m = Matrix.CreateTranslation(0, 0) * this.TransformToVisual(_parent).Value; and then creating a point: Point p = new Point(m.M31, m.M32);, but check if it works first (for example with points (1, 0), (0, 1), (2, 1) and compare with WPF).
4. Use LayoutTransformControl.

[maxkatz6]

code at WPF gets access to keyboard and mouse without having PointerEventArgs available

Which is not a good practice.
Also you are free to store and reuse last values of those events.

[mcmikecreations]

So is my best bet right now with #4447, #4062 and device state checks is to write my own InputDevice (since KeyboardDevice will be removed before 1.0) based on the existing one add the required functionality there?

[workgroupengineering]

Which is not a good practice.
Also you are free to store and reuse last values of those events.

Why?

I don't understand why to dirty the ViewModel to intercept events to memorize the status of some keys.

I prefer in such a thing:

class MyVM:BaseViewModel
{
    readonly IInputManager _currentInputManager;
    public MyVm(IInputManager manager) => 
       _currentInputManager = manager;
       
    public void Do(object parameter)
    {
         var capslockState = _currentInputManager
                .PrimaryKeyboardDevice.GetKeyStates(VirtualKey.CapsLock)
         switch (capslockState)
         {
           .....
         }
    }
} 

[maxkatz6]

PrimaryKeyboardDevice

My concern was with multiple devices (and sometimes multiple types of them).
In some cases defining and using "primary" device will solve this concern. Not saying that it's unusual to have two keyboards (there is on screen virtual keyboards though).

But with pointer input devices it's more complicated since user can have mouse and stylus/pen, both can be used in some drawing application and using "primary" one will be questionable.

As you have InputManager with primary keyboard device, it could be possible to have input manager with all connected devices with ability to read their state. Although it probably won't work well on some specific OSs (I don't have information about this at least).

[kekekeks]

I'd suggest to have a separate "NonPortableApis" package that would expose whatever APIs it wants