Better way to output stdout to WPF UI

I need to run and watch some slow bat-files in our system from a WPF/C# user interface.
The user interface should not wait for the process to end but display it whenever something happens in the bat file.

The following code works for now but introduced a thread to handle it.

        private void OnClick(object sender, RoutedEventArgs e)
        {
            Thread thread1 = new Thread(() =>
            {
                System.Diagnostics.Process p = new System.Diagnostics.Process();
                p.StartInfo.WorkingDirectory = "C:\my\folder\with\batfile";
                p.StartInfo.FileName = "cmd.exe";
                p.StartInfo.Arguments = "/C run.bat";
                p.StartInfo.UseShellExecute = false;
                p.StartInfo.CreateNoWindow = true;
                p.StartInfo.RedirectStandardOutput = true;
                p.StartInfo.RedirectStandardError = true;
                p.EnableRaisingEvents = true;

                p.OutputDataReceived += P_OutputDataReceived;
                p.Start();
                p.BeginOutputReadLine();
                p.WaitForExit(20000);
            }
            );
            thread1.Start();
        }
        private void P_OutputDataReceived(object sender, DataReceivedEventArgs e)
        {
            if (!string.IsNullOrEmpty(e.Data))
            {
                lvConsoleOutput.Dispatcher.Invoke(() =>
                {
                    m_ConsoleRows.Add(e.Data);
                });
            }
        }

A few notes:
lvConsoleOutput is a regular listview that is associated with m_ConsoleRows which is an ObservableCollection<string>.

The contents of a sample run.bat file here:

echo 1
echo 2
timeout 2
echo more text 3
timeout 1
echo almost the end
timeout 3
echo DONE!

By not running this in a thread, the entire UI freezes until the entire bat file has run until completion. Then I get the output in the UI and it unfreezes again.
With thread1 above I get the achieved result but...

My questions are:

Can I do this without introducing a thread?

Are there cleaner ways to achieve this?

> By not running this in a thread, the entire UI freezes until the entire bat file has run until completion.

That is because of the WaitForExit call. Just remove it:

private void OnClick(object sender, RoutedEventArgs e)
{
    System.Diagnostics.Process p = new System.Diagnostics.Process();
    p.StartInfo.WorkingDirectory = @"C:\my\folder\with\batfile";
    p.StartInfo.FileName = "cmd.exe";
    p.StartInfo.Arguments = "/C run.bat";
    p.StartInfo.UseShellExecute = false;
    p.StartInfo.CreateNoWindow = true;
    p.StartInfo.RedirectStandardOutput = true;
    p.StartInfo.RedirectStandardError = true;
    p.EnableRaisingEvents = true;
    p.OutputDataReceived += P_OutputDataReceived;
    p.Start();
    p.BeginOutputReadLine();
}

As a note, since you are directly accessing the ListBox anyway, you do not strictly need the ObservableCollection as its ItemsSource. This works as well with less code:

private void P_OutputDataReceived(object sender, DataReceivedEventArgs e)
{
    if (!string.IsNullOrEmpty(e.Data))
    {
        lvConsoleOutput.Dispatcher.Invoke(() => lvConsoleOutput.Items.Add(e.Data));
    }
}