What determines the monitor my app runs on?

Question

I am using Windows, and I have two monitors.

Some applications will always start on my primary monitor, no matter where they were when I closed them.

Ot

Answer 1

So I agree there are some apps that you can configured to open on one screen by maximizing or right clicking and moving/sizing screen, then close and reopen. However, there are others that will only open on the main screen.

What I've done to resolve: set the monitor you prefer stubborn apps to open on, as monitor 1 and the your other monitor as 2, then change your monitor 2 to be the primary - so your desktop settings and start bar remain. Hope this helps.

Answer 2

Important note: If you remember the position of your application and shutdown and then start up again at that position, keep in mind that the user's monitor configuration may have changed while your application was closed.

Laptop users, for example, frequently change their display configuration. When docked there may be a 2nd monitor that disappears when undocked. If the user closes an application that was running on the 2nd monitor and the re-opens the application when the monitor is disconnected, restoring the window to the previous coordinates will leave it completely off-screen.

To figure out how big the display really is, check out GetSystemMetrics.

Answer 3

Correctly written Windows apps that want to save their location from run to run will save the results of GetWindowPlacement() before shutting down, then use SetWindowPlacement() on startup to restore their position.

Frequently, apps will store the results of GetWindowPlacement() in the registry as a REG_BINARY for easy use.

The WINDOWPLACEMENTroute has many advantages over other methods:

• Handles the case where the screen resolution changed since the last run: SetWindowPlacement() will automatically ensure that the window is not entirely offscreen
• Saves the state (minimized/maximized) but also saves the restored (normal) size and position
• Handles desktop metrics correctly, compensating for the taskbar position, etc. (i.e. uses "workspace coordinates" instead of "screen coordinates" -- techniques that rely on saving screen coordinates may suffer from the "walking windows" problem where a window will always appear a little lower each time if the user has a toolbar at the top of the screen).

Finally, programs that handle window restoration properly will take into account the nCmdShow parameter passed in from the shell. This parameter is set in the shortcut that launches the application (Normal, Minimized, Maximize):

if(nCmdShow != SW_SHOWNORMAL)
    placement.showCmd = nCmdShow; //allow shortcut to override

For non-Win32 applications, it's important to be sure that the method you're using to save/restore window position eventually uses the same underlying call, otherwise (like Java Swing's setBounds()/getBounds() problem) you'll end up writing a lot of extra code to re-implement functionality that's already there in the WINDOWPLACEMENT functions.

Answer 4

It's not exactly the answer to this question but I dealt with this problem with the Shift + Win + [left,right] arrow keys shortcut. You can move the currently active window to another monitor with it.

Answer 5

I'm fairly sure the primary monitor is the default. If the app was coded decently, when it's closed, it'll remember where it was last at and will reopen there, but -- as you've noticed -- it isn't a default behavior.

EDIT: The way I usually do it is to have the location stored in the app's settings. On load, if there is no value for them, it defaults to the center of the screen. On closing of the form, it records its position. That way, whenever it opens, it's where it was last. I don't know of a simple way to tell it to launch onto the second monitor the first time automatically, however.

-- Kevin Fairchild

Answer 6

Do not hold me to this but I am pretty sure it depends on the application it self. I know many always open on the main monitor, some will reopen to the same monitor they were previously run in, and some you can set. I know for example I have shortcuts to open command windows to particular directories, and each has an option in their properties to the location to open the window in. While Outlook just remembers and opens in the last screen it was open in. Then other apps open in what ever window the current focus is in.

So I am not sure there is a way to tell every program where to open. Hope that helps some.