Question

I’m making a program that downloads a photo from the internet and saves it to a file called “temp.jpg”. My program user BackgroundWorker and I have a problem for example, the second time I run the BackgroundWorker my program tries to open “temp.jpg” but it’s still being using by the first BackgroundWorker.

Any advice how to solve this?

A solution could be naming the file by a timestamp or something like that.

To donwload the photo to temp.jpg I’m using

WebClient webClient = new WebClient();
try
{
    webClient.DownloadFile(foto, path);
}
catch (Exception ex)
{
    MessageBox.Show(ex.Message);
} 

the problem is that “temp.jpg” is being used by the first BackgroundWorker.

Answer 1

EDIT

WebClient.DownloadFile handles the management of the file stream for you so, this is not a problem with your disposal of stream objects or release of file handles.

You need to ensure that each concurrent call to WebClient.DownloadFile is using a unique filename.

Unique temporary file names can be generated by the framework using the Path.GetTemporaryFileName method.

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You should ensure you are closing the the files and releasing the handle in you background worker, this is generally achecived with a using block around the IDisposable file stream.

If you want to download files concurrently i.e. on multiple background workers at once, then each worker will need a unique file name but, if this is a problem for a repeated run of a single background worker, unique names is not the right solution. Hiding the problem by using new unique filenames will just leak resources.