What are &H1, &H8000, etc.?

[Ovatvvon]

Hi, I'm just wondering if anyone could tell me what &H1 is, or what &H8000 means, etc?

Public Const VK_SHIFT = &H10
Public Const VK_CAPITAL = &H14
Public Const VK_CONTROL = &H11

Dim IsShifted As Boolean
Dim IsCaps As Boolean
Dim IsCtrl As Boolean

IsCaps = (GetKeyState(VK_CAPITAL) And &H1) 'Caps
IsShifted = (GetKeyState(VK_SHIFT) And &H8000) 'Shift Key
IsCtrl = (GetKeyState(VK_CONTROL) And &H8000) 'Ctrl Key

-Ovatvvon :-Q

 

[ADoozer]

&H means the number is hexadecimal (ie base 16)

&H1 = decimal 1
&H8000 = decimal 32768

u can use the windows calculator to swap between diffent bases to try these out for yourself

If somethings hard to do, its not worth doing - Homer Simpson

 

[Ovatvvon]

Hmm, so I'm confused then. For the case of the "IsShifted" variable: Would something like that be detecting if the KeyCode value for shift (&H10) has been entered, and adds the value of &H8000 to it? Or, what's the purpose of &H8000?

-Ovatvvon :-Q

 

[Sheco]

Did you look at the MSDN page for the GetKeyState function?

Here is the link:

http://msdn.microsoft.com/library/d...erence/keyboardinputfunctions/getkeystate.asp

I think the answer you seek can be found in this part:

[b]Return Value[/b]

The return value specifies the status of the specified virtual key, as follows: 

If the high-order bit is 1, the key is down; otherwise, it is up.

If the low-order bit is 1, the key is toggled. A key, such as the CAPS LOCK key, is toggled if it is turned on. The key is off and untoggled if the low-order bit is 0. A toggle key's indicator light (if any) on the keyboard will be on when the key is toggled, and off when the key is untoggled.

 

[Sheco]

So the GetKeyState return value is data type SHORT... So it is a 16 bit number... just like a VB INT.

I will do the rest in a code box so it uses the courier font so everything lines up...

In binary VK_SHIFT (&H10) would be:       0000000000000010
So if Shift is down, GetKeyState returns: 1000000000000010
In binary &H8000 lights up the top bit:   1000000000000000

So use bitwise AND to test like this... 
     1000000000000010
 AND 1000000000000000
---------------------
   = 1000000000000000

 

[Ovatvvon]

So if I want to check whether the ALT key has been pressed or not, am I correct in believing that it is of value &H12 and it should be assigned the &H8000?

So if I wanted to make a function, for instance, that copied the text from an inputbox to the clipboard when the user selected ALT and X, I would type the following (minus a few lines declaring functions and such to save space and time)???

Public Const VK_ALT = &H12
Public Type KBDLLHOOKSTRUCT
    vkCode As Long ' virtual keycode
    scanCode As Long ' hardware scancode
    flags As Long
    time As Long
    dwExtraInfo As Long
End Type

Dim IsALT As Boolean

IsALT = (GetKeyState(VK_ALT) And &H8000) 'Ctrl Key
tempVKCodeHolder = correctedInputValues(CInt(Trim(HookStruct.vkCode))) 'Takes the interpreted keyboard input value and translates it to it's proper ascii value.

If ((IsAlt = True) And (tempVKCodeHolder = 88)) Then
  'If ALT and "X" are pressed at the same time,
  'the user's data Copied to the Clipboard.

  Clipboard.Clear
  Clipboard.SetText (strUserInput)
  Exit Function
End If

-Ovatvvon :-Q