Multiple UI threads in a windows forms application

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This is my first question here...
I hope someone will be able to help me....
I have a form which has two panels.. one panel is for video player and other one is for ticker(label which moves from right to left)...
Problem is that this ticker moves fine when the video is playing.. but it pauses when the video is completed and new video is loaded... I am using windows media player.. And both video and the ticker is playing on a different thread...
Here's my piece of code..

C#

private void Form_Load(object sender, EventArgs e)
    {
          
        System.Threading.ThreadStart starter = delegate
        {
          videoplayer();
        };
        new System.Threading.Thread(starter).Start();
          

        System.Threading.ThreadStart SecondThread = delegate
        {
            tickerplayer();
        };
        new System.Threading.Thread(SecondThread).Start();
    }

here's my code for ticker

C#

private void tickerplayer()
{
    tckr.Font = new Font("Arial", 10, FontStyle.Bold);
    tckr.BackColor = Color.Transparent;
    tckr.ForeColor = Color.Black;
    tckr.Parent.BackColor = Color.Gray;
    tckr.Text = "Denzel Washington";
    tckr.TextAlign = ContentAlignment.MiddleCenter;
    System.Windows.Forms.Timer t = new System.Windows.Forms.Timer();
    t.Interval = 1;
    t.Start();
    t.Tick += (sender, EventArgs) =>
    {
        int z, hgt;
        hgt = tckr.Location.Y;
        z = tckr.Location.X;

        if (z <= 0 - tckr.Width)
            z = tckr.Parent.Width - 0;
        else
            z = tckr.Location.X - 3;

        tckr.Location = new Point(z, hgt);

    };
}

and this is for video

C#

void wp2_PlayStateChange(object sender, _WMPOCXEvents_PlayStateChangeEvent e)
{
    if (wp2.playState == WMPPlayState.wmppsPlaying)
    {
        if (play == true)
        {
            media = wp1.newMedia(@"D:\Parafait Home\Signage\ctvc_JOE.avi");
            play = false;
            wp1.currentMedia = media;
            wp1.Ctlcontrols.stop();
        }
    }
    if (wp2.playState == WMPPlayState.wmppsMediaEnded)
    {
        wp2.currentPlaylist.clear();
        play = true;
        wp1.Ctlcontrols.play();
    }
    return;
}

void wp1_PlayStateChange(object sender, _WMPOCXEvents_PlayStateChangeEvent e)
{
    if (wp1.playState == WMPPlayState.wmppsPlaying)
    {
        if (play == true)
        {
            media = wp2.newMedia(@"D:\Parafait Home\Signage\ctvc_BAYER.AVI");
            play = false;
            wp2.currentMedia = media;
            wp2.Ctlcontrols.stop();
        }
    }
    if (wp1.playState == WMPPlayState.wmppsMediaEnded)
    {
        wp1.currentPlaylist.clear();
        play = true;
        wp2.Ctlcontrols.play();
    }
    return;
}

private void videoplayer()
{
    media = wp1.newMedia(@"D:\Parafait Home\Signage\ctvc_JOE.avi");
    play = true;
    wp1.currentMedia = media;
}

Posted 12-Sep-13 1:03am

Sachin Athrady

Updated 12-Sep-13 1:43am

CPallini

v2

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Rob Philpott · Answer 1 · 2013-09-12T01:35:00

Solution 1

Firstly, welcome!

I'm suprised you aren't getting any exceptions thrown as you are breaking the cardinal rule in GUI programming that only the thread which creates a control can update it.

First of all, don't call tickerplayer on a background thead. Call that on the main thread and see what happens. All it does is set up a timer and those calls to set the ForeColor/BackColor should not be done on a background thread

The timer takes care of the 'asynchronous' aspects of updating the ticker - this should be used on the main thread.

Also, when you paste code try and put it in a code block (formatting) or people will get huffy. It's an odd place this...

Edit - I don't think you should be explicitly creating threads at all. The Timer will do your ticker, the video player should take care of itself.

Posted 12-Sep-13 1:35am

Rob Philpott

Updated 12-Sep-13 1:37am

v2

Comments

Sachin Athrady 12-Sep-13 7:47am

Sir.. this is my new approach... Calling each player as separate ui thread.. but it still doesnt do it for me... same problem.. here each player is in form1(video) and form2(ticker) respectively.. code is same..

namespace replicaThread
{
public partial class Form3 : Form
{
public Form3()
{
InitializeComponent();

Thread thread1 = new Thread(() =>
{
Form2 f2 = new Form2();
Application.Run(f2);
});
thread1.ApartmentState = ApartmentState.STA;
thread1.Start();

Thread thread = new Thread(() =>
{
Form1 f1 = new Form1();
Application.Run(f1);
});
thread.ApartmentState = ApartmentState.STA;
thread.Start();
}
}
}

Rob Philpott 12-Sep-13 8:14am

Interesting that. So now you have two main windows, fully independent and you are still getting this issue? Again it's an odd way you are doing it. Rather than do that in the constructor of Form3, do it in the Main() function. Even so though I think you've got sufficient isolation that they shouldn't interfere with each other. Have a look in task manager and see how busy you computer gets when swapping videos.

Sachin Athrady 12-Sep-13 8:23am

yea.. Exactly i played only ticker this time... commented whole video thread.. now only ticker is playing... and now i open up a video in windows media player outside the application.. Same problem still exists.. Now this is hard bro....

Rob Philpott 12-Sep-13 12:34pm

Yes. Good luck - I don't see how you can fix that.

Sachin Athrady 12-Sep-13 7:48am

as i am new to this.. i dont knw how to ident my code here..