Using Delphi to write multi-screen programs

Not now. Some POS machines are dual-screen (such as Casiva POS machine), a screen can be used when the customer display, when idle can also display some ads. In fact, using Delphi to write a dual-screen program is relatively simple, screen.monitorcount is the current number of system screen, Tform also have screen-related properties, such as Defalumonitor, But I want to set a form to show on which screen it looks like there is no property (I may not have found it), but the study VCL code found how to display a form on a screen (see Tcustomform's Setwindowtomonitor method) and extract it to encapsulate it as a function:

Form: Target form Monitorindex: Shows on which screen 0 is the current screen, 1 is the 2nd screen ....

Procedure Setformmonitor (form:tcustomform; Monitorindex:integer);
Begin
if (monitorindex>-1) and (Monitorindex<screen.monitorcount) then//ensure that the screen index is within range
Begin
Form.setbounds (Screen.monitors[monitorindex]. Left + ((Screen.monitors[monitorindex]. Width-form.width) Div 2),
Screen.monitors[monitorindex]. Top + ((screen.monitors[monitorindex). Height-form.height) Div 2),
Form.width, Form.height);
End
End

After that, you want to show which form is on which screen to tune the function.