Stopping a task

I was looking for a way to stop a task by clicking on a button. My program performs some very complex calculation, and I want to add the feature of stopping the number crunching in the middle by clicking on a button or a custom ActiveX control. Any suggestions?
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if you want to stop ececution of a function, when some button is clicked, you should add a Module Level Boolean.
when the button is clicked - you set this boolean to TRUE.
now, in the function (to be stopped), add here and there a :
 if SomeBoolean=True then
     exit sub\function
 end if

if the function contains loop(s), you should insert the *DoEvents* statment
into the loops in order to enable buttun click event.

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Here's a little example:

Option Explicit
Private bStop As Boolean

Private Sub Command1_Click()
    'Flag that we want to stop the operation
    bStop = True
End Sub

Private Sub Form_Load()
    bStop = False
    'Start the long operation
    Call LongOperation
End Sub

Private Sub LongOperation()
    Dim i, j As Double
    For i = 1 To 30000
        j = i - (4 * Atn(1))
        Text1.Text = Format(j, "#0.0000")
        DoEvents 'Yield to other events
        If bStop Then Exit For 'Exit if True
    bStop = False
End Sub
skamal021899Author Commented:
I really appreciate your example, erick37. It very helpful.
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Visual Basic Classic

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