How to exit a While loop when key pressed

[sohan]

hello !!! i am new in VB

the program below is onli small part ,, at the moment i only want to put it into do while loop which can be stop using any keyboard button

is there any way i acn do it ???

thankxxxxxx

[CODE=vb]While (temp_time >= 0)
T1 = Timer
DT = 0
Stop_async1 = 0
Half_ready = 0

While (Half_ready = 0) 'And (Stop_async1 = 0)
result = D2K_AI_AsyncDbl BufferHalfReady (Card_number, Half_ready, Stop_async1)
If result < 0 Then
box = MsgBox("ERROR", vbYesNo)
End If
Wend
result = D2K_AI_AsyncDbl BufferToFile(Ca rd_number)
'While (Stop_async1 = 0)
' result = D2K_AI_AsyncChe ck(Card_number, Stop_async1, Access_count)
'Wend
'result = D2K_AI_AsyncCle ar(Card_number, 0, Access_count)
T2 = Timer
DT = T2 - T1
temp_time = temp_time - DT
DT_temp = DT_temp + DT
If DT_temp >= 1 Then
DT_temp = 0
Info_Label.Capt ion = "Remained time: " + Str$(temp_time) + " sec."
END IF
Wend[/CODE]

[Killer42]

That shouldn't be too hard. Just create a global or form-level boolean variable, and exit the loop if you find that the value is True.

Then, on your form, set the .KeyPreview property to True, and in the KeyPress or KeyDown event procedure, set the boolean variable to True.

This will work for VB6 - VB.Net is different in many ways, so may require a different technique. You didn't say which you're using.

[sohan]

thx killer42 but i didnt quite catch u as i am totally lay man in VB , will that be possible for you to explain with simple example.

i am using VB 6

thanks a lot

[Killer42]

thx killer42 but i didnt quite catch u as i am totally lay man in VB , will that be possible for you to explain with simple example.
i am using VB 6

Ok, here's a very simple program which demonstrates the concept.

Create a new project. Add a form, go to the code window for the form, and paste in this code (replacing anything already there)...

[CODE=vb]Option Explicit

Private Sub Form_KeyPress(K eyAscii As Integer)
UserWantsOut = True
End Sub[/CODE]

Add a code module, and paste this code into it...

[CODE=vb]Option Explicit

Public UserWantsOut As Boolean

Sub Main()
Dim Xlimit As Long, Ylimit As Long
Load Form1
DoEvents
Xlimit = Form1.ScaleWidt h
Ylimit = Form1.ScaleHeig ht
Randomize
Form1.Show
Do Until UserWantsOut
Form1.PSet (Rnd * Xlimit, Rnd * Ylimit), RGB(Rnd * 255, Rnd * 255, Rnd * 255)
DoEvents
Loop
End Sub[/CODE]

In the Project Properties, set the startup object to Sub Main. Then, when you run it, this should display the form and start filling it with randomly-coloured dots until you press any key, then stop.

Be warned, though - if you use your mouse to close the window, then the keypress will never happen, so the loop will keep running forever (or until you tell VB to stop). After all, it's only a simple demo program. I suppose I should have set the UserWantsOut variable to True in the form's QueryUnload event procedure, but got a bit lazy.

[Helmer]

hey if u can get a chart for the keycodes of the keys on a keyboard, im sure u are all familiar with a case statement...
form keydown event

select case Keycode

case vbkeyX' x=keycode

here u put wat u want t happen wen that key is hit

case vbkeyY y=keycode

here u put wat u want t happen wen that key is hit

end select

or more efficiently

if keycode <>0 then
...
end if

for most keys the keycode is the keyname ex K's keycode is vbkeyK, etc

[sohan]

thanks guys thanks a lot

[LacrosseB0ss]

hey if u can get a chart for the keycodes of the keys on a keyboard, .....

All this is is a simple ASCII chart. Type that in Google and you'll get umpteen bajillion hits (both web, and image). If you're looking for foreign language (not English) characters you'll need to check up "Extended ASCII Chart" but same deal.

[Killer42]

All this is is a simple ASCII chart. Type that in Google and you'll get umpteen bajillion hits (both web, and image).

Just look in your VB doco.

[LacrosseB0ss]

Just look in your VB doco.

hmm, I didn't know it was there too. Thanks killer!

[Killer42]

hmm, I didn't know it was there too. Thanks killer!

No prob. :)

From memory, I think the easiest way to track it down is to look up SendKeys.