help dispose of image

[talahaski]

Can somebody please help me dispose of a image, I want to delete the image afterwards and the OS is holding it.

simple code I thought would work, but does not.

dim imagetoload as string="c:/temp.jpg"
Dim img As Image
try
img.FromFile(ImageToLoad)
catch
messagebox.show("Image is corrupt")
end try
img.Dispose()
If optx = 1 Then
Copy(ImageToLoad, NewFileName)
else
File.Delete(ImageToLoad)
end if


This blows up at the img.dispose() statement.

 

[wessamzeidan]

whats the error youre getting??

 

[talahaski]

I think the problem might be that I have other lock issues too. I definitly have some major resource leaks. I dont have the code with me right now so it will have to wait until tonight before I can post more info.

Are there any good free tools that can check your source code for resource leaks?

 

[talahaski]

ok, here is the error

At run time I get the following error


An unhandled exception of type system.nullReferenceException occurred

Additional info - object reference not set to an instance of an object


Any ideas?

 

[talahaski]

Heres the full source

Please help with resource leaks and this image.dispose error.


Private Sub ImportPhoto(ByVal ImageToLoad As String)
Dim MaxImageNumber As Integer = 0
Dim NewFileName As String
Dim CheckDupResult As Integer = 0
Dim img As Image
img.FromFile(ImageToLoad)
MaxImageNumber = GetMaxImageNumber()
MaxImageNumber = MaxImageNumber + 1
NewFileName = PhotosetPath + CStr(MaxImageNumber) + GetExtension(ImageToLoad)
img.Dispose()
If ImportCheckForDuplicate = 1 Then
CheckDupResult = CheckDuplicate(ImageToLoad)
End If
If CheckDupResult = 0 Then
Try
Copy(ImageToLoad, NewFileName)
If ImportDeleteSource = 1 Then
Try
File.Delete(ImageToLoad)
Catch
MessageBox.Show("error deleting source file")
End Try
End If
Catch
MessageBox.Show("Error copying image")
errors = 1
End Try
End If
End Sub


Private Function GetMaxImageNumber() As Integer
Dim filestr As String
Dim Max As Integer = 0
If Directory.Exists(PhotosetPath) Then
For Each filestr In Directory.GetFiles(PhotosetPath)
If IsNumeric(Path.GetFileNameWithoutExtension(filestr)) Then
If CInt(Path.GetFileNameWithoutExtension(filestr)) > Max Then
Max = Path.GetFileNameWithoutExtension(filestr)
End If
End If
Next
End If
Return Max
End Function


Private Function CheckDuplicate(ByVal PrimaryFile As String) As Integer
Returns 0 if no duplicates,
returns 1 if duplicate found
Dim filestr As String
Dim rtn As Integer = 0
Dim Hash As New System.Security.Cryptography.MD5CryptoServiceProvider
Dim PrimaryHashBytes As Byte() = Hash.ComputeHash(New FileStream(PrimaryFile, FileMode.Open, FileAccess.Read))
Try
If Directory.Exists(PhotosetPath) Then
For Each filestr In Directory.GetFiles(PhotosetPath)
Dim Hash2 As New System.Security.Cryptography.MD5CryptoServiceProvider
Dim CompareHashBytes As Byte() = Hash2.ComputeHash(New FileStream(filestr, FileMode.Open, FileAccess.Read))
Try
If System.Text.ASCIIEncoding.ASCII.GetString(PrimaryHashBytes) = System.Text.ASCIIEncoding.ASCII.GetString(CompareHashBytes) Then
Duplicatefile1 = PrimaryFile
Duplicatefile2 = filestr
Duplicate = 0
frmIShowDuplicate.ShowDialog()
If Duplicate = 1 Then
rtn = 1
End If
End If
Catch
MessageBox.Show("Error ASCIIEncoding")
End Try
Hash2.Clear()
Next
End If
Catch
MessageBox.Show("Error Directory does not Exist")
End Try
Hash.Clear()
Return rtn
End Function

 

[wessamzeidan]

ok I think I got it

img=img.FromFile(ImageToLoad)

try it and let me know

 

[talahaski]

isnt this doing the same thing?

Dim img As Image
img.FromFile(ImageToLoad)

 

[wessamzeidan]

I dont think so since Image.FromFile() is a shared method that returns an instance of Image

 

[talahaski]

It worked!

Not quite sure why it worked, but it did.


Thanks a million wessamzeidan

 

[wessamzeidan]

As I told you, because FromFile() is a shared method,

you can do this too
img=Image.FromFile(FileName)

 

[talahaski]

darn.


The dispose is working great, but now my delete statement is NOT working.

File.Delete(ImageToLoad)


Something else must be holding a lock on this file.

 

[wessamzeidan]

check to see that youve closed all open files, you functions open files, so check them out

 

[talahaski]

Yah, Im going through it one function at a time checking the OS to see when it locks the file.

It looks like its coming from the function CheckDuplicate now.

Something about the hashing that I must be leaving open.

 

[talahaski]

I thought the hash.clear() was cleaning up everything, but it looks like its not.


Any idea on how to clean up after these?

Dim Hash As New System.Security.Cryptography.MD5CryptoServiceProvider
Dim PrimaryHashBytes As Byte() = Hash.ComputeHash(New FileStream(PrimaryFile, FileMode.Open, FileAccess.Read))

 

[talahaski]

Ok,

I got this fixed.

Thanks for all the help everybody.

I had to change around the checkduplicate function, added some closes and set=nothing

Here is the completed function



Private Function CheckDuplicate(ByVal PrimaryFile As String) As Integer
Returns 0 if no duplicates,
returns 1 if duplicate found
Dim filestr As String
Dim rtn As Integer = 0
Dim fs1 As FileStream
Dim fs2 As FileStream
Dim fs2Open As Integer = 0

fs1 = New FileStream(PrimaryFile, FileMode.Open, FileAccess.Read)

Dim Hash As New System.Security.Cryptography.MD5CryptoServiceProvider
Dim PrimaryHashBytes As Byte() = Hash.ComputeHash(fs1)
Dim CompareHashBytes As Byte()
Try
If Directory.Exists(PhotosetPath) Then
For Each filestr In Directory.GetFiles(PhotosetPath)
Check if file ext are the same, if not skip compare
If GetExtension(filestr) = GetExtension(PrimaryFile) Then
fs2open = 1
Dim Hash2 As New System.Security.Cryptography.MD5CryptoServiceProvider
fs2 = New FileStream(filestr, FileMode.Open, FileAccess.Read)
CompareHashBytes = Hash2.ComputeHash(fs2) New FileStream(filestr, FileMode.Open, FileAccess.Read))

Try
If System.Text.ASCIIEncoding.ASCII.GetString(PrimaryHashBytes) = System.Text.ASCIIEncoding.ASCII.GetString(CompareHashBytes) Then
Duplicatefile1 = PrimaryFile
Duplicatefile2 = filestr
Duplicate = 0
frmIShowDuplicate.ShowDialog()
If Duplicate = 1 Then
rtn = 1
End If
End If
Catch
MessageBox.Show("Error ASCIIEncoding")
End Try
CompareHashBytes = Nothing
Hash2.Clear()
End If
Next
End If
Catch
MessageBox.Show("Error Directory does not Exist")
End Try
PrimaryHashBytes = Nothing
Hash.Clear()
fs1.Close()
If fs2Open = 1 Then
fs2.Close()
End If
Return rtn
End Function