ARTICLE

Multi Threaded File Reader and Generator

Posted by steven lopez Articles | Windows Forms C# March 07, 2006
The attached source code with this article is a multithreaded application written using .NET 2.0 that shows how to use the background worker threads to read a text file, generate reports and show report progress and completed events.
Reader Level:
Download Files:
 

The attached source code with this article is a multithreaded application written using .NET 2.0 that shows how to use the background worker threads to read a text file, generate a report and show the report progress and completed events on the UI.

It also uses File.ReadAllBytes and File.WriteAllBytes from System.Io class. Microsoft says these methods are faster than the previous version. This apllies to File.ReadAllLines and File.WriteAllLines. It also shows how to use and update the progressbar with the background worker.

When you run the attached application, you will see the following form, where you can select a source data and destinatiomn and clicking on the Transform button will start transforming the data and show the progress of the process in the progress bar.

MutImg1.jpg

The Transform button click event handler looks like following:

//Event when user tries to transform data.

        private void btnTransform_Click(object sender, EventArgs e)

        {

            //Reset processing values.

            count = 0;

            proc = true;

            watch.Reset();

            //set number of files to registry.

            regkey.SetValue("numfiles", txtNumfiles.Text.ToString(), RegistryValueKind.String);

            //get # of files and apply to progress bar maximum value.

            totalfiles = Convert.ToInt64((String)regkey.GetValue("numfiles"));

            progressBar1.Maximum = Convert.ToInt32(totalfiles);

            //Notify Ui processing has begun and disable button.

            btnTransform.Text = "Processing";

            btnTransform.Enabled = false;

            //Check if there is a path to get data if not

            //show error reset Ui and return

            if (txtSourceData.Text.Length == 0)

            {

                MessageBox.Show("No data is loaded, select a file to load data from.");

                //Set Ui to process again.

                btnTransform.Text = "Transform";

                btnTransform.Enabled = true;

                return;

            }

            //Check if there is a destination path if not

            //show error reset Ui and return

            if (txtDestination.Text.Length == 0)

            {

                MessageBox.Show("There is no path inputed, please input a path to write to");

                //Set Ui to process again.

                btnTransform.Text = "Transform";

                btnTransform.Enabled = true;

                return;

            }

            //Reads the bytes of data from the selected file.

            if (txtSourceData.Text.Length > 0)

            {

                try

                {

                    data = File.ReadAllBytes(txtSourceData.Text.ToString());

                    //Retrieves the original selected file without the full path

                    //and without the extension.

                    sourcefilename = Path.GetFileNameWithoutExtension(openFileDialog.FileName.ToString());

                }

                catch (System.Exception caught)

                {

                    MessageBox.Show(caught.Message);

                }

            }

            //Check to make sure backgroud worker is not busy with

            //another request and call it to process.

            if (WorkerMain.IsBusy == false)

                WorkerMain.RunWorkerAsync();

}

And the worker thread code looks like following:

//Event when worker reports progress.

        private void WorkerMain_Progress(object sender, ProgressChangedEventArgs e)

        {

            //Updates Ui after worker reports progress.

            label3.Text = count + " files";

            progressBar1.Value = count;

           

        }

        //Event when worker completes processing.

        private void WorkerMain_Complete(object sender, RunWorkerCompletedEventArgs e)

        {

            try

            {

                //Calculates the amount of megabytes generated

                //by the worker.

                totalbytes = data.Length * count;

                totalmb = totalbytes / 1049725;

                //Stops the stop watch.

                watch.Stop();

                //Gives user notification that the process completed and the statistics.

                MessageBox.Show("Transformed " + count + " files. In " + watch.Elapsed.Minutes.ToString() +

                    " minutes " + watch.Elapsed.Seconds.ToString() + " seconds." +

                    " With a total of " + totalmb + " Megabytes.");

                //Sets Ui so the user can process again.

                btnTransform.Text = "Transform";

                btnTransform.Enabled = true;

            }

            //Silently resets Ui.

            catch (System.Exception caught)

            {

                //Logs error to event log I try this in case

                //eventlog is full.

                try

                {

                    label3.Text = "Failed";

                    eventid++;

                    log.WriteEntry(caught.Message, EventLogEntryType.Error, eventid);

                }

                catch

                {

                }

                //Set Ui to process again.

                btnTransform.Text = "Transform";

                btnTransform.Enabled = true;

            }

        }


 

COMMENT USING
Employers - Post Free Jobs