Odd GetPixel Error - Memory overload - Program crash without an error

Basicly I quickly wrote a simple version which translate a small icon in a numerical signature, the only problem is i can use it because after it is ran a couple of times my program crashes without an error; the window moves and becomes unusable(And in my taskmanager window I can see the memory increase by 100kb a time).
I have tryed disabling all other functions in the loop and the only function that causes this problem is the function with GetPixel in it.

I hope anybody with experience can solve my problem, here is the piece of code that causes the trouble:

Code:

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Public Function analyseCard(ByVal hwnd As Long, ByVal realX As Long, realY As Long) As String
Dim X As Long
Dim Y As Long
Dim cardValue As Long
    DoEvents
    realX = realX - 1
    realY = realY - 1
    For Y = realY To realY + 10
        For X = realX To realX + 9
            If GetPixel(GetDC(hwnd), X, Y) = vbWhite Then
                DoEvents
                cardValue = cardValue + (X - realX) + (Y - realY)
            End If
        Next
    Next
   
    Select Case cardValue
    Case 78
        analyseCard = "A"
    Case 52
        analyseCard = "B"
    Case 70
        analyseCard = "C"
    Case 72
        analyseCard = "D"
    Case 76
        analyseCard = "E"
    Case 8
        analyseCard = "F"
    Case 105
        analyseCard = "G"
    Case 73
        analyseCard = "H"
    Case 181
        analyseCard = "I"
    Case 69
        analyseCard = "J"
    Case 71
        analyseCard = "K"
    Case 43
        analyseCard = "L"
    Case 63
        analyseCard = "M"
    End Select
End Function

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It looks alright to me though..

Thanks,
Pascal.

Welcome to the forums.

Your routine is causing memory leaks.

This part of your code is generating your error. Here's MSDN's official documentation and note remarks pertaining to ReleaseDC

Code:

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GetDC(hwnd)

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Recommend two things
1. Define new variable in routine: tgtDC As Long
2. Modify your GetPixel call. A bit awkward due to your DoEvents within the loop

Code:

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    For Y = realY To realY + 10
        For X = realX To realX + 9

            If tgtDC = 0& Then tgtDC = GetDC(hWnd) ' << added

            If GetPixel(tgtDC, X, Y) = vbWhite Then ' << modified
                ReleaseDC hWnd, tgtDC ' << added
                tgtDC = 0& ' << added
                DoEvents
                cardValue = cardValue + (X - realX) + (Y - realY)
            End If
        Next
    Next
    If tgtDC Then ReleaseDC hWnd, tgtDC ' << added
....

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Thank you very much, your first solution has worked:
1. Define new variable in routine: tgtDC As Long