此 BackgroundWorker 声明它不报告进度

Question

Where is my mistake? I think everything is fine but still I see this exception:

Exception {"This BackgroundWorker states that it doesn't report progress. Modify WorkerReportsProgress to state that it does report progress."}.Exception wasthrown in _worker.ReportProgress((int)(progressPercentage*100)).

Can somebody recommend me a ftp server with rich data for test download and upload?

Here is my code:

    this._worker = new BackgroundWorker();

    this._worker.WorkerSupportsCancellation = true;
    this._worker.WorkerSupportsCancellation = true;

    this._worker.ProgressChanged += backgroundWorker1_ProgressChanged;
    this._worker.DoWork += backgroundWorker1_DoWork;

using (FileStream fs = new    FileStream(Path.Combine(this._ftpInfo.SaveDirectory, this._ftpInfo.FileName), FileMode.CreateNew, FileAccess.Write))
                    {


                byte[] buffer = new byte[1024];
                    int len;
                    int byteTotal = 0;

                    while ((len = stream.Read(buffer, 0, buffer.Length)) > 0)
                    {
                        await fs.WriteAsync(buffer, 0, len);
                        byteTotal += len;
                        double index = (double)(byteTotal);
                        double total = (double)buffer.Length;
                        double progressPercentage = (index / total);
                        _worker.ReportProgress((int)(progressPercentage*100));

                    }
                    fs.Close();

Answer 1

You have this line twice:

this._worker.WorkerSupportsCancellation = true;

One of those was probably supposed to be:

this._worker.WorkerReportsProgress = true;

On a side note, consider using Task.Run with IProgress<T> instead of BackgroundWorker . The resulting code will be shorter and more type-safe.

Answer 2

您必须从对象属性中将 WorkerReportsProgress 设置为 True