[RESOLVED] VS 2017 GDI Memory Leak

I have the following as member variables of a UserControl for my football simulation game.

Code:

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    Private m_Logo() As Image
    Private m_imPassing(5) As Image
    Private m_imRushing(5) As Image
    Private m_imReceiving(5) As Image
    Private m_imTackles(5) As Image

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This UserControl simulates games and updates the screen with info as each game finishes. m_imRushing and the other variables listed above are the team logos associated with the stat leaders in each category (ranked 1 through 5). Drawing these images in Paint is what's causing my error (which comes in the form of "Parameter is not Valid").

Here's more background information: I use m_Logo() to store the images of each team in the UCs Load event where m_League is an object my own class (CLeague) that stores all league information.

Code:

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        ReDim m_Logo(m_League.NumberOfTeams - 1)
        For x = 0 To m_League.NumberOfTeams - 1
            m_Logo(x) = ResizeLogo(m_League.Team(x).Logo)
        Next

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My ResizeLogo function takes the stored large logo and shrinks it so it fits nicely next to a player's name:

Code:

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    Private Function ResizeLogo(ByVal OriginalLogo As Image)

        ' Make a bitmap for the result.
        Dim bm_dest As New Bitmap(24, 24)

        '' Make a Graphics object for the result Bitmap.
        Dim gr_dest As Graphics = Graphics.FromImage(bm_dest)

        '' Copy the source image into the destination bitmap.
        gr_dest.DrawImage(OriginalLogo, 0, 0, bm_dest.Width + 1, bm_dest.Height + 1)

        bm_dest.Dispose()
        gr_dest.Dispose()


        Return bm_dest
    End Function

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When the user clicks a button "Sim All Games" a loop is started to simulate each game of the week

Code:

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        For x = 0 To GameCount - 1
              'Tons of processing code not relevant
              m_imPassing(1) = m_Logo(m_League.Team(x).TeamIndex)
              m_imRushing(1) = m_Logo(m_League.Team(x).TeamIndex)       
              'etc...
        next

---

So my member variables are set. I call Invalidate() after every game is simmed which is supposed to update the Logos. After about a minute of successful execution I receive the dreaded "Parameter not valid" error for the DrawImage call.

Code:

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      Private Sub pnWeeklyLeaders_Paint(ByVal sender As System.Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles pnWeeklyLeaders.Paint
            Dim g As Graphics = e.Graphics
            Dim y As Byte
            Dim LogoSpace As Byte = 27
            For y = 0 To 4
                  Dim LogoLocation As New Point(37, 82 + (y * LogoSpace))
                  If m_pbPassing(y) IsNot Nothing Then g.DrawImage(m_imPassing(y), LogoLocation)
            Next

      end sub

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There's something about using the UCs member variables that's causing memory usage to build up. When I take out the logos drawing routine I can run through almost the entire week's worth of games before the error shows up (there may be another lesser leak as well, but one problems at a time for this post) Where is this memory buildup and how should I dispose it? I can't dispose m_imPassing and the other variables because I reuse them do to their scope. There are no IDisposable objects to dispose either.

Thanks!
neef

Your ResizeLogo method doesn't really make sense. You create a Bitmap, dispose it and then return it. You presumably then use that Bitmap later, so there's no wonder you have issues. You are supposed to dispose a Bitmap - or any object - AFTER you have finished using it. Don't dispose it first.

Also, it's not a memory leak. A memory leak is a specific thing. There's no memory being leaked here.

Quote:

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Originally Posted by jmcilhinney

Your ResizeLogo method doesn't really make sense. You create a Bitmap, dispose it and then return it. You presumably then use that Bitmap later, so there's no wonder you have issues. You are supposed to dispose a Bitmap - or any object - AFTER you have finished using it. Don't dispose it first.

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bm_dest is commented out in my actual code but I erased the apostrophe when I transferring the text to this thread - my bad. I still have the error.

Quote:

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Originally Posted by jmcilhinney

Also, it's not a memory leak. A memory leak is a specific thing. There's no memory being leaked here.

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What could cause a "Parameter is not Valid Error" in the paint event then? The error pops up after the code works for over a minute. When I take out all code relevant to drawing my logos I don't get the eroor at all. This error is so frustrating because it's so vague!

If you want help with code that's not working, I suggest showing us the code that's not working.

It's working. It turned out it was bm_dest.dispose like you correctly identified. That line wasn't commented out as I wrote in my last post. Just carelessness on my part.

I have another issue but that'll wait for tomorrow if I can't fix it. Until then, thanks JMC.