BINDEVENT GetKeyState

[newtofoxpro]

PUBLIC ofrm
ofrm = CREATEOBJECT("MyForm")
ofrm.show(1)
RETURN

DEFINE CLASS MyForm as Form
    AutoCenter=.T.
	ADD OBJECT txt1 as textbox 
	ADD OBJECT txt2 as textbox WITH Top=50
	ADD OBJECT cmd as commandbutton WITH top = 100, Height=100, Width=thisform.width, Visible=.F.
  	PROCEDURE Init
        DECLARE integer GetKeyState IN User32 integer
  		BINDEVENT(This.HWnd,0x0100,This,"DetectCtrlKeyDn")
 		BINDEVENT(This.HWnd,0x0101,This,"DetectCtrlKeyUp")
  		BINDEVENT(This.HWnd,0x0104,This,"DetectAltKeyDn")
 		BINDEVENT(This.HWnd,0x0105,This,"DetectAltKeyUp")
	ENDPROC
 	PROCEDURE DetectCtrlKeyDn(p1,p2,p3,p4)
	   IF bittest(GetKeyState(0x11),7)
          this.cmd.Caption="Ctrl"
          this.cmd.Visible=.T.
       ENDIF
	PROCEDURE DetectCtrlKeyUp(p1,p2,p3,p4)
	   this.cmd.Visible=.F.
 	PROCEDURE DetectAltKeyDn(p1,p2,p3,p4)
       this.cmd.Caption="Alt"
       this.cmd.Visible=.T.
	PROCEDURE DetectAltKeyUp(p1,p2,p3,p4)
	   this.cmd.Visible=.F.
ENDDEFINE

1. If I press F10 Alt key works. I need only Alt key should work.
2. Arrow keys not working. I need only Ctrl key should work.

What I am missing ? Please help me.

Best Regards.

 

[Olaf Doschke]

Well, look at the definition of the windows messages you're binding to.

0x0100:

https://docs.microsoft.com/en-us/windows/desktop/inputdev/wm-keydown

0x0101:

https://docs.microsoft.com/en-us/windows/desktop/inputdev/wm-keyup

0x0104:

https://docs.microsoft.com/en-us/windows/desktop/inputdev/wm-syskeydown

0x0105:

https://docs.microsoft.com/en-us/windows/desktop/inputdev/wm-syskeyup

They are not about CTRL and ALT, the first two are about any key while ALT is not pressed the others about any key while ALT is pressed.

Program a handler just outputting p1-p4 and see how these values come in when you press keys. Notice the parameter values will differ for ALT, ALT Gr, Left and Right CTRL key, left and right SHIFT key, when akey is hold down for a while and when pressed in combination with other keys.

Bye, Olaf.

Olaf Doschke Software Engineering

https://www.doschke.name