What's wrong with my application ---- Size was 0, but I expected 46806 !

Question

I'm a C# programmer.

Now, I'm using the ICSharpCode.SharpZipLib.dll to create a zip file in my current project. But it occurs to me that when I click the button at the SECOND TIME to execute a function to create a zip file, the application will throw an exception, friendly and seriously told me that "Size was zero, but I expected 46086".

I'm so confused that I want to know why? When I click the button at the first time, I can do it successfully without any error.

My related codes are as follows:

internal void ThreadProc()
{
    try
    {
        ZipHelper.CreateZip(backupZipFile, Constants.HomeConstant, true);

        // do other things
    }

}

The CreateZip() function's realization is as follows:

public static void CreateZip(string zipFileName, string sourceDirectory, bool recurse)
{
 FastZip zip = new FastZip();

 if (File.Exists(zipFileName))
 {
         File.Delete(zipFileName);
 }

 zip.CreateZip(zipFileName, sourceDirectory, true, "");
}

Now, I will show you the recursive calling process:

1. Call method "UpdateAppAsync" in "ActiveCheckManager" class

public void UpdateAppAsync(string masterConfig)
{
    this.masterConf = masterConfig;

    Thread actualThread = new Thread(new ThreadStart(UpdateApp));
    actualThread.IsBackground = true;
    actualThread.CurrentCulture = Thread.CurrentThread.CurrentCulture;
    actualThread.CurrentUICulture = Thread.CurrentThread.CurrentUICulture;
    actualThread.Start();
}

2. Call the UpdateApp function asynchronously, in the UpdateApp method, it will only call the UpdateDetail function simply.

private void UpdateDetail(string masterConfig, string category)
{
    IUpdate worker = new HP.ActiveCheckLocalMode.UpdateEngine.UpdateManager();
    worker.UpdateApp(masterConf);
}

3. The worker.UpdateApp will call UpdateDetail(string, UpdateCategory) only.

private void UpdateDetail(string masterConfig, UpdateCategory cat)
{
    UpdateThread updateThread = new UpdateThread(this, cat);
    updateThread.MasterConfig = masterConfig;
    updateThread.ThreadProc();
}

That is the calling process. When I click the update button second time, it will throw an exception, can you help me? Thank you very much.

Answer 1

Has the first task thread finished before you start the second time?

I would imagine that File.Delete() and some items in the SharpZipLib to not respond nicelly to multithreadingly zip the same folder simultaneously to the same file.

Promote that " UpdateThread updateThread " as a private member of the "ActiveCheckManager" class, then check if it is already running from a previous click before creating a new thread.