Duplicate Windows form on multiple screen in c#

Question

I am developing a feedback system for an automotive company. On the billing desk, there is a dual monitor setup: one for a billing person and one for a customer who's giving feedback. My need is to duplicate a Windows form on both screens, as mirror images, So that the billing person can see what feedback the customer is giving.

I am using the code below for display on the secondary screen:

 Screen[] sc;
        Form f = new Form();
        sc = Screen.AllScreens;
        f.FormBorderStyle = FormBorderStyle.None;
        f.Left = sc[1].Bounds.Left;
        f.Top = sc[1].Bounds.Top;
        f.Height = sc[1].Bounds.Height;
        f.Width = sc[1].Bounds.Width;
        f.StartPosition = FormStartPosition.Manual;
        f.Show();

However, it will not mirror the form on the primary screen. I had also referred to the duplicate window question, but it will create different instances for the same form, which will not mirror the Windows form. How can I mirror it on both screens?

Answer 1

One possible way to do it would be to capture the form that is inputting the data to a image on a timer (use a reasonable delay so that it's "almost realtime") and use it on a PictureBox on the secondary form. To capture the form to a image you do:

Bitmap bmp = new Bitmap(form.Width, form.Height);
form.DrawToBitmap(bmp, new Rectangle(Point.Empty, bmp.Size));

Then you assign bmp as the image to the PictureBox on the other form.

I've made a quick sample project and uploaded it here: https://www.dropbox.com/s/pjuk3zvpbglhodb/SOTestMirror.zip?dl=0

Lacks opening the form on the secondary screen and styling, but shows a possible way to do it

The result is:

For the record: I have no clue why when DrawToBitmap is called on a form it copies to the bitmap using a Windows 7 chrome instead of the Windows 8 one... that's interesting, to say the least (and I'd say a bug). That's running on Win 8.1. (Since I haven't seen this mentioned anywhere, I've opened a bug on Connect: https://connect.microsoft.com/VisualStudio/feedback/details/1059444/in-windows-8-drawtobitmap-on-a-form-draws-the-windows-7-chrome)

Answer 2

Here are simple code that take a screenshot from the extended screen and display in the picture box. you can save to image file as well.

Add this code in timer to refresh screen at some interval.

private Bitmap bmpScreenshot;
bmpScreenshot = new Bitmap(Screen.AllScreens[1].Bounds.Width,
                                           Screen.AllScreens[1].Bounds.Height,
                                           PixelFormat.Format32bppArgb);

Graphics.FromImage(bmpScreenshot).CopyFromScreen(Screen.AllScreens[1].Bounds.X,
                                         Screen.AllScreens[1].Bounds.Y,
                                         0,
                                         0,
                                         Screen.AllScreens[1].Bounds.Size,
                                         CopyPixelOperation.SourceCopy);

pictureBox1.Image = bmpScreenshot;
pictureBox1.Refresh();
GC.Collect();

you also can get the screenshot of primary screen.