DPI exception of window form dynamically created by WPF

There is a requirement in the project , Need to be in WPF Click the button in the main form to create a sub form , The position of the child form needs to move with the parent form , On multiple screens and individual screens dpi In different situations , The initial value of a dynamically created form at the time of creation dpi Is the screen where the program runs （ Simply speaking , For example, there is a screen 1、2, On screen 1 Double click on the icon to run the program , Then drag the program to the screen 2 Up , The screen 1 Is the initial screen for the program to run , Dynamically created subform dpi The initial value is the same as the screen 1 Of dpi identical ）, At this time, when you move the subform according to the coordinates, the coordinate calculation error will appear , And the problem only occurs at the beginning .
terms of settlement ： After dynamically creating a subform , The subform needs to call show Method , Then get the zoom ratio of the sub form at this time

var source = PresentationSource.FromVisual(myWindow);
if (source != null)
    dpiRatio = source.CompositionTarget.TransformToDevice.M11;

Also use the same method to get the parent form at this time dpi, Then according to two dpi Calculate the corresponding coordinates