====== KEYSTATE property (System) ======


 
==== Description ====
 
 
This property returns:
 
 
 
1. The state of a key at the time the last message was read from the Presentation Server’s message queue (the key to check is passed as a virtual-key code in the index parameter), or
 
2. An array representing the state of all virtual keys if no virtual key code is passed.
 
 
 
 
==== Property Value ====
 
 
If a virtual-key code was specified this property is an integer value that represents a set of bit flags.  As a general rule:
 
 
 
• If the key is pressed down the property returns a value < 0 (i.e. The most significant bit is set), otherwise the key is not pressed.
 
• If the key is toggled (such as the CAPS-LOCK key) then the least significant bit is set (this only applies to keys that can be toggled)
 
 
 
If a virtual-key code was not specified this property returns an @fm-delimited array of flags for all virtual keys (this is a 256-element array) – the meaning of the flags is as described above.
 
 
 
See remarks for more information.
 
 
 
 
==== Property Traits ====
 
 
 
^Development^Runtime^Indexed^Scaled^Synthetic^
|N/A|Get|Yes|No|No|

 


 
==== Remarks ====
 
 
This property is essentially a wrapper around the GetKeyState and GetKeyboardState Windows API functions, so please refer to the documentation on the Microsoft website for further information.
 
 
 
Virtual-key code constants are defined in the MSWin_VirtualKey_Equates insert record.
 
 
 
 
 
 
==== Example ====
 
<code>
 
$Insert msWin_VirtualKey_Equates

   

   // Get the state of the Shift key

   ShiftDown = ( Get_Property( "SYSTEM", "KEYSTATE", VK_SHIFT$ ) < 0 )

   

   // Get the state of the CAPS-LOCK key

   CapState   = Get_Property( "SYSTEM", "KEYSTATE", VK_CAPITAL$ )

   CapPressed = ( CapState < 0 )

   CapToggled = BitAnd( CapState, 0x01 )

   

   // Get the state of all keys and extract the CAPS-LOCK state

   KeyboardState = Get_Property( "SYSTEM", "KEYSTATE" )

   CapState = KeyboardState<VK_CAPITAL$>
 
 
 

</code>

 
==== See Also ====
 
 
ASYNCKEYSTATE property