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Image to memory stream

Posted on 2006-11-28
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Last Modified: 2010-04-23
I have a function i'm using to generate an md5 off an image

 Dim MD5ImageStream As New IO.MemoryStream(ayfile)

ayfile represents "capacity as integer"

I was using Dim ayFile() As Byte = ConnectStreamToByteArray(oStream)
before. Now I'm using


   Dim oImage As Image = Image.FromStream(oStream)

What would I pass to md5imagestream in place of ayfile?
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Question by:JPERKS1985
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Expert Comment

by:Hillwaaa
ID: 18033988
Hi JPERKS1985,

try something like this (from: http://www.dotnet247.com/247reference/msgs/22/112124.aspx):

        Dim myImage As Image
        Dim ms As New IO.MemoryStream
        myImage.Save(ms, System.Drawing.Imaging.ImageFormat.Bmp)
        Dim b(ms.Length - 1) As Byte
        ms.Position = 0
        ms.Read(b, 0, ms.Length)

Cheers,
Hillwaaa
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Author Comment

by:JPERKS1985
ID: 18034062
That doesn't seem to work. Thanks for your help thus far. The stream is created this way

  Dim oStream As Stream = oResponse.GetResponseStream

I must be able to pass the finished product to

  Private Function MD5_Hash(ByVal Fs As Stream) As String
            Dim md5 As New MD5CryptoServiceProvider
            Dim hash() As Byte

            Try

                hash = md5.ComputeHash(Fs)

                Fs.Close()
                md5.Clear()

                Return BitConverter.ToString(hash).Replace("-", "").ToUpper
            Catch ex As Exception
                'MsgBox(ex.Message.ToString)

                Return Nothing
            End Try

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Accepted Solution

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Hillwaaa earned 500 total points
ID: 18034096
Ok, not sure if I'm confused now, but i thought you wanted a replacement for ayfile, so something like this:

Dim oImage As Image = Image.FromStream(oStream)
Dim MD5ImageStream As New IO.MemoryStream
oImage.Save(MD5ImageStream, System.Drawing.Imaging.ImageFormat.Bmp)
Dim hash As String = MD5_Hash(MD5ImageStream)

Is that what you wanted?
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Author Comment

by:JPERKS1985
ID: 18034121
sorry I'm starying to confuse myself,

I used to use




        Private Function ConnectStreamToByteArray(ByVal poStream As Stream) As Byte()

            Dim obj45 As Object = New Object

            SyncLock obj45

                Dim ayRet() As Byte
                Dim icnt As Integer
                Try
                    Do
                        ReDim Preserve ayRet(icnt)
                        '* Read the Byte into the array
                        ayRet(icnt) = poStream.ReadByte
                        '* Increment
                        icnt = (icnt + 1)
                    Loop
                Catch ex As Exception
                    '* Do nothing. The Stream is Completed
                End Try
                '* Return the Byte Array

                Return ayRet


            End SyncLock


        End Function

To convert ostream into the proper format, however that was slowing down the thread. Now I need an alternative to either use ostream to convert to the proper formatfrom either oimage or ostream or even a modficatio to the hash function so I can pass the oimage directly.
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LVL 16

Expert Comment

by:Hillwaaa
ID: 18034161
What happens when you try the following (I'm assuming that you already have oImage as an Image - and you might need to change the image format to the appropriate format):

Dim MD5ImageStream As New IO.MemoryStream
oImage.Save(MD5ImageStream, System.Drawing.Imaging.ImageFormat.Bmp)
Dim hash As String = MD5_Hash(MD5ImageStream)
Messagebox.show(hash)

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LVL 1

Author Comment

by:JPERKS1985
ID: 18034190
You got it man , I get a good hash (thats not the default blank hash). Thanks for the help id buy you a drink if we wern't online. haha
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LVL 16

Expert Comment

by:Hillwaaa
ID: 18034201
lol - no worries!  buy it anyway and drink it for me :)
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