C#

public class Uploader
{
    public event EventHandler<EventArgs<UploadProgress>> ProgressChanged;
    public event EventHandler<EventArgs<RunWorkerCompletedEventArgs[]>> Completed;

    private BackgroundWorker backGroundWorkerData;
    private BackgroundWorker backGroundWorkerFile;
    private BackgroundWorker backGroundWorkerPhoto;

    private RunWorkerCompletedEventArgs[] result;

    public void RunAsync()
    {
        result = new RunWorkerCompletedEventArgs[3];

        backGroundWorkerData = new BackgroundWorker();
        backGroundWorkerData.WorkerReportsProgress = true;
        backGroundWorkerData.WorkerSupportsCancellation = true;
        backGroundWorkerData.DoWork += new DoWorkEventHandler(backGroundWorkerData_DoWork);
        backGroundWorkerData.ProgressChanged += new ProgressChangedEventHandler(backGroundWorkerData_ProgressChanged);
        backGroundWorkerData.RunWorkerCompleted += new RunWorkerCompletedEventHandler(backGroundWorkerData_RunWorkerCompleted);
        backGroundWorkerData.RunWorkerAsync();
        // and the same for the other workers
    }

    // These three methods will need implementing for all workers.
    void backGroundWorkerData_DoWork(object sender, DoWorkEventArgs e)
    {
        // Do upload stuff here plus check backGroundWorkerData.CancellationPending
    }
    void backGroundWorkerData_ProgressChanged(object sender, ProgressChangedEventArgs e)
    {
        OnProgressChanged(
            new EventArgs<UploadProgress>(
                new UploadProgress(DataType.Data, e.ProgressPercentage)));
    }
    void backGroundWorkerData_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
    {
        result[0] = e;
        backGroundWorkerData = null;
        CheckCompleted();
    }

    public void CancelAsync()
    {
        backGroundWorkerData.CancelAsync();
        backGroundWorkerFile.CancelAsync();
        backGroundWorkerPhoto.CancelAsync();
    }
    private void CheckCompleted()
    {
        if (backGroundWorkerData == null &&
            backGroundWorkerFile == null &&
            backGroundWorkerPhoto == null)
            OnCompleted(new EventArgs<RunWorkerCompletedEventArgs[]>(result));
    }
    protected virtual void OnProgressChanged(EventArgs<UploadProgress> e)
    {
        EventHandler<EventArgs<UploadProgress>> eh = ProgressChanged;
        if (eh != null)
            eh(this, e);
    }
    protected virtual void OnCompleted(EventArgs<RunWorkerCompletedEventArgs[]> e)
    {
        EventHandler<EventArgs<RunWorkerCompletedEventArgs[]>> eh = Completed;
        if (eh != null)
            eh(this, e);
    }
}
public class UploadProgress
{
    public UploadProgress(DataType dataType, int progress)
    {
        DataType = dataType;
        Progress = progress;
    }

    public DataType DataType { get; private set; }
    public int Progress { get; private set; }
}
public enum DataType
{
    Data = 0,
    File = 1,
    Photo = 2
}
public class EventArgs<T> : EventArgs
{
    public EventArgs(T value)
    {
        Value = value;
    }

    public T Value { get; private set; }
}

if(eventArgs.Cancelled)
{
MainWorker = null;
}

eawedat wrote:

do believe that this forum has been made to ask/answer questions.
and was not made for complaining and blaming each others.

eawedat wrote:

second i was seeking all the day for free-uploading website to upload a screen-shot which explains the situation of the error easily.

eawedat wrote:

third, do u have to reply to your question?

eawedat wrote:

http://img251.imageshack.us/img251/3733/err2.gif[^]

eawedat wrote:

i do believe that this forum has been made to ask/answer questions.

eawedat wrote:

I got the answer already by a good guy in here,
Discussion has been closed.
NO more comments please.
lol

eawedat wrote:

I posted my whole project just to ease it.

I believed that if i posted the whole project it would be easier to open it
with an colorful editor and see the codes right inside there.

eawedat wrote:

with regards to the code snippet it would not help because it's small part.