- By default, your application will open in a normal window, in one of three states: each can be set when the program launches (Load() event), or changed at runtime. The "normal" state means visible on screen, but not maximized. Here's how to set and change these three states:
this.WindowState = FormWindowState.Normal; // optionally centered-on-screen
this.WindowState = FormWindowState.Maximized;
this.WindowState = FormWindowState.Minimized; // App can start that way too!Note: user-configured shortcuts can override startup state. (Right-click on the shortcut, choose "Properties", select the "Shortcut" tab, and pick another value from the "Run" dropdown).
- To switch to full-screen mode, change the application's FormBorderStyle property to "None":
this.FormBorderStyle = FormBorderStyle.None; - Removing visible borders will likely leave you with a window without title bar, which you can only resize with the WinKey+Up keyboard shortcut (Windows 7 / 8), so we'll have to resize and reposition the main program window based on the current screen resolution.
To move the active form to the top right corner of the active monitor:this.Left = 0;
this.Top = 0; - To force the application to occupy the entire screen:
this.Width = SystemInformation.VirtualScreen.Width;
this.Height = SystemInformation.VirtualScreen.Height; 
You can resize and position your main window based on the available real estate left by the taskbar; keep in mind that the taskbar can be docked against any side of the screen, and resized up to half of the screen height / width. And these dimensions vary between Classic and Aero themes.
Top, Right, Bottom, and Left will tell you where the taskbar is currently positioned, and how high (vertical taskbar) or wide (horizontal taskbar) it is. The screenshot may help clarify.// Loop through all screen and get its specs
foreach( Screen screen in Screen.AllScreens ) {
MessageBox.Show(
screen.WorkingArea.Width // Available horizontal space, in pixels
+"\n"+
screen.WorkingArea.Height // Working vertical space available
+"\n"+
screen.WorkingArea.Top // Start of available vertical real estate
// Etc.
);
}Note: if your program launches in full screen mode, it will take up the entire available screen real estate, including the taskbar area (which is then hidden). If you toggle the full-screen mode at runtime, the next time you go full-screen will end up being a "hybrid mode", which partially hides behind the taskbar. But during the initial full-screen mode, the window can be minimized, the user can use Alt+Tab to switch between it and other applications, and your program will remain in a "true" full-screen mode, completely hiding the taskbar when it is the active window.