How do I update a progress bar as soon as Process gives StandardOutput?

Question

I built this simple form to illustrate my issue:

What I need:

1. Execute a script that I have in python (built an .exe from pyinstaller) clicking on "button1"
2. Update the progress bar and the label with the percentage the python script prints out as soon as it prints.

What I've got:

• The code works fine, does what I need, but not as soon as the script print the percentage.

Here's my code:

private static double value= 0;

private void button1_Click(object sender, EventArgs e)
{
    Process process = new Process();
    process.StartInfo.FileName = @"C:\Users\User\Desktop\testeProgresso.exe";
    process.StartInfo.UseShellExecute = false;
    process.StartInfo.RedirectStandardOutput = true;
    process.OutputDataReceived += new DataReceivedEventHandler((_sender, _e) =>
    {
        // Prepend line numbers to each line of the output.
        if (!String.IsNullOrEmpty(_e.Data))
        {
            value= double.Parse(_e.Data);
        }
    });

    process.Start();
    process.BeginOutputReadLine();
    process.WaitForExit();

    label1.Text += value.ToString();
    progressBar1.Value = (int)value;

    process.WaitForExit();
    process.Close();
}

I need it does so when the process is finished, I'll close this form and open another.

EDIT:

private void button6_Click(object sender, EventArgs e)
        {
            Process process = new Process();
            process.StartInfo.FileName = @"C:\Users\User\Desktop\testeProgresso.exe";
            process.StartInfo.UseShellExecute = false;
            process.StartInfo.RedirectStandardOutput = true;
            process.SynchronizingObject = this;
            process.EnableRaisingEvents = true;
            process.Exited += (s, evt) => { process?.Dispose();};
            process.OutputDataReceived += new DataReceivedEventHandler((_sender, _e) =>
            {
                
                if (!String.IsNullOrEmpty(_e.Data))
                {
                    value = double.Parse(_e.Data);
                    label1.Text += value.ToString();
                    progressBar1.Value = (int)value;
                    
                }
            });

            process.Start();
            process.BeginOutputReadLine();
            //process.Close();
        }

as Jimi suggested, I made some changes. But it still just updates the whole thing after the process is done. Plus, I couldnt implement the Exited event, because I dont know how.

Answer 1

So, after all the information exchange with Jimi, down in the comments, I solved the problem. I used all his suggestions and adjusted my c# code to this:

 private static double value = 0;
 private void button1_Click(object sender, EventArgs e)
        {
            string path = @"your path here";
            Process process = new Process();
            process.StartInfo.FileName = path;
            process.StartInfo.UseShellExecute = false;
            process.StartInfo.RedirectStandardOutput = true;
            process.SynchronizingObject = this;
            process.EnableRaisingEvents = true;

            process.Exited += (s, evt) => {

                process?.Dispose();
            };
            process.OutputDataReceived += new DataReceivedEventHandler((_sender, _e) =>
            {

                if (!String.IsNullOrEmpty(_e.Data))
                {
                    value = double.Parse(_e.Data);
                    label1.Text = value.ToString() + "%";
                    progressBar1.Value = (int)value;

                }
            });

            process.Start();
            process.BeginOutputReadLine();
        }      

The code was doing what it was supposed to do, but I was not getting the results I wanted because my Python script was not giving any StandardOutput. So, I went back to python and made this adjustment to the printing lines:

print(percentage, flush=True)

And now life is good. Thank you, Jimi!