How to use process using Threads without stoping a timer in WPF? [closed] - wpf

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This is a little guide to help resolve a problem with timers that stops when opening a file using process to open it with the default application.
If you are using a timer in C# WPF you will notice that the timer will stop working until the file has been closed which may not be the behavior that you want.
Let say for instance that you want a timer to start as soon as the file you want to show to the user is open. While the user sees or read the file you want the timer to continue. Without using a Thread the timer will not continue it's work up until the file is closed.
This is the problem encountered:
I have a timer that is started by pressing a button (btnTache1) but it stops when I'm using System.Diagnostics.Process to open a file with it's default application using another button (btnVideo1). It only resume after the file is closed.
This a brief description of the components of the program:
There is a button to show the media called btnVideo1
The onclick event of the button defines a timer _timer1 and the file to show to the user _media1 and a countdown used by the timer _startingTimer1 set to 30 seconds.
Here is the code:
private int _startingTimer1;
private string _media1;
DispatcherTimer _timer1 = new DispatcherTimer();
private void btnVideo1_Click(object sender, RoutedEventArgs e)
{
_startingTimer1 = 30; // 30 seconds
// stop timer if already started
if (_timer1.IsEnabled == true)
{
_timer1.Stop();
}
// configure timer
_timer1 = new DispatcherTimer();
_timer1.Interval = TimeSpan.FromSeconds(1);
_timer1.Tick += timer_Tick1;
_timer1.Start();
// defining the file to show to the user
string procedure = "procedure1.mp4"
_media1 = "//10.10.0.1/Procedures/ + procedure;
ShowVideo(_media1);
}
// Action done when a tick for timer occur
private void timer_Tick1(object sender, EventArgs e)
{
// decreasing countdown
_startingTimer1--;
// calculate and show the timer (countdown)
TimeSpan time = TimeSpan.FromSeconds(_startingTimer1);
tbxTemps1.Text = time.ToString();
// if timer under 0
if (_startingTimer1 < 0)
{
// change background color depending on number
if (_startingTimer1 % 2 == 0)
btnTemps1.Background = new SolidColorBrush(Colors.OrangeRed);
else
btnTemps1.Background = new SolidColorBrush(Colors.LightGray);
}
}
// show the file to the user
private void ShowVideo(string media)
{
try
{
// define a process to show the file
System.Diagnostics.Process process = new System.Diagnostics.Process();
// declare the path to the file
process.StartInfo.FileName = new Uri(media, UriKind.Absolute).ToString();
process.StartInfo.UseShellExecute = true;
// start the process to show the file to the user
process.Start();
process.WaitForExit();
}
catch
{
MessageBox.Show("Could not open the file.", "Error", MessageBoxButton.OK, MessageBoxImage.Warning);
}
}

Answer 1

To resolve the issue the use of a Thread really comes handy. Calling the function using a thread makes the timer continue in the primary thread while other things are done in parallel in another thread. To achieve this here's what I have changed.
I changed the ShowVideo method as follow:
private void ShowVideo(string media)
{
try
{
System.Diagnostics.Process process = new System.Diagnostics.Process();
process.StartInfo.FileName = new Uri(media, UriKind.Absolute).ToString();
process.StartInfo.UseShellExecute = true;
Thread showFile = new Thread(() => process.Start());
showFile.Start(); // start the Thread
showFile.Join();
showFile.WaitForExit();
}
catch
{
MessageBox.Show("Could not open the file.", "Error", MessageBoxButton.OK, MessageBoxImage.Warning);
}
}