Want to protect your cyber security and still get fast solutions? Ask a secure question today.Go Premium

x
?
Solved

Object Disposed Exception

Posted on 2014-04-02
7
Medium Priority
?
329 Views
Last Modified: 2014-04-02
I'm getting this error...

System.ObjectDisposedException: Cannot access a closed Stream.     at System.IO.__Error.StreamIsClosed()     at System.IO.MemoryStream.Seek(Int64 offset, SeekOrigin loc)

I haven't disposed of the stream in question.. so who has ?

Are streams cleaned up differently ? The stream in question is defined at class level.

Any ideas?
0
Comment
Question by:Dodsworth
  • 3
  • 2
  • 2
7 Comments
 
LVL 75

Expert Comment

by:käµfm³d 👽
ID: 39972194
It would help to see the code in question.
0
 
LVL 1

Author Comment

by:Dodsworth
ID: 39972309
I've chopped the code down so it's easier to read, which has prompted a thought..
When I dispose of e.ImageStream is mainStream also being disposed because I'm using '=' ?

Partial Public Class Camera

    Private mainStream As Stream    'This is where I'm holding the image stream from the camera
    Private saveNow As Boolean = True   'Save the image straight away or on click of save button

    Private Sub cam_CaptureImageAvailable(ByVal sender As Object, ByVal e As Microsoft.Devices.ContentReadyEventArgs)
        Try
            mainStream = e.ImageStream
            If saveNow Then
                saveImage() 'This call does not error
            End If
        Catch err As Exception
            Stop
        Finally
            e.ImageStream.Close()
        End Try
    End Sub

    Private Sub saveImage()
        mainStream.Seek(0, SeekOrigin.Begin)
        library.SavePictureToCameraRoll(Date.UtcNow.Ticks.ToString & ".jpg", mainStream)
    End Sub

    Private Sub Ok_Click(sender As Object, e As EventArgs)
        saveImage() 'Here Errors :(
    End Sub
End Class

Open in new window

0
 
LVL 52

Accepted Solution

by:
Carl Tawn earned 2000 total points
ID: 39972428
Basically the stream is being disposed by the line:
e.ImageStream.Close()

Open in new window

At which point your mainStream variable now holds a reference to a disposed object.
0
Concerto's Cloud Advisory Services

Want to avoid the missteps to gaining all the benefits of the cloud? Learn more about the different assessment options from our Cloud Advisory team.

 
LVL 1

Author Comment

by:Dodsworth
ID: 39972461
Thought that might be the case. So I need to copy the e.Imagestream to mainStream somehow?
0
 
LVL 52

Expert Comment

by:Carl Tawn
ID: 39972480
Or remove the line:
e.ImageStream.Close()

Open in new window

From your Finally clause, and then close the stream when you are done with it (probably in your SaveImage() method.
0
 
LVL 75

Expert Comment

by:käµfm³d 👽
ID: 39972587
So I need to copy the e.Imagestream to mainStream somehow?
You can use the Clone method for this purpose.

and then close the stream when you are done with it (probably in your SaveImage() method.
But you'll also want to include some checking on the state of that variable, in case someone clicks the button twice. I'd suggest setting the variable to Nothing after you close the image, and then add a check for Is Nothing in your save code.
0
 
LVL 1

Author Comment

by:Dodsworth
ID: 39972722
It would seem that e.ImageStream goes out of scope outside cam_CaptureImageAvailable.

I tried
e.ImageStream.CopyTo(mainStream)

Open in new window

but got a ArgumentNullException which the documentation indicates that is because the destination is Nothing.  
Private mainStream As New Stream

Open in new window

Resulted in
'New' cannot be used on a class that is declared 'MustInhert'
So I changed it to
Private mainStream As New MemoryStream

Open in new window

And all is well :)
0

Featured Post

Restore individual SQL databases with ease

Veeam Explorer for Microsoft SQL Server delivers an easy-to-use, wizard-driven interface for restoring your databases from a backup. No expert SQL background required. Web interface provides a complete view of all available SQL databases to simplify the recovery of lost database

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Wouldn’t it be nice if you could test whether an element is contained in an array by using a Contains method just like the one available on List objects? Wouldn’t it be good if you could write code like this? (CODE) In .NET 3.5, this is possible…
Simulator games are perfect for generating sample realistic data streams, especially for learning data analysis. It is even useful for demoing offerings such as Azure stream analytics, PowerBI etc.
Screencast - Getting to Know the Pipeline
Enter Foreign and Special Characters Enter characters you can't find on a keyboard using its ASCII code ... and learn how to make a handy reference for yourself using Excel ~ Use these codes in any Windows application! ... whether it is a Micr…
Suggested Courses
Course of the Month14 days, 15 hours left to enroll

577 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question