This is how you create those flashing Taskbar icons.
Form1.Designer.cs
Added to private void InitializeComponent (bottom of method)
FlashWindow.Tray(this);
Added under the private void InitializeComponent method
public static class FlashWindow
{
[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool FlashWindowEx(ref FLASHWINFO pwfi);
/// Stop flashing. The system restores the window to its original state.
public const uint FLASHW_STOP = 0;
/// Flash the window caption.
public const uint FLASHW_CAPTION = 1;
/// Flash the taskbar button.
public const uint FLASHW_TRAY = 2;
/// Flash both the window caption and taskbar button.
/// This is equivalent to setting the FLASHW_CAPTION | FLASHW_TRAY flags.
public const uint FLASHW_ALL = 3;
/// Flash continuously, until the FLASHW_STOP flag is set.
public const uint FLASHW_TIMER = 4;
/// Flash continuously until the window comes to the foreground.
public const uint FLASHW_TIMERNOFG = 12;
[StructLayout(LayoutKind.Sequential)]
private struct FLASHWINFO
{
/// The size of the structure in bytes.
public uint cbSize;
/// A Handle to the Window to be Flashed. The window can be either opened or minimized.
public IntPtr hwnd;
/// The Flash Status.
public uint dwFlags;
/// The number of times to Flash the window.
public uint uCount;
/// The rate at which the Window is to be flashed, in milliseconds. If Zero, the function uses the default cursor blink rate.
public uint dwTimeout;
}
/// Flash the specified Window (Form) until it receives focus.
public static bool Flash(System.Windows.Forms.Form form)
{
// Make sure we're running under Windows 2000 or later
if (Win2000OrLater)
{
FLASHWINFO fi = Create_FLASHWINFO(form.Handle, FLASHW_ALL | FLASHW_TIMERNOFG, uint.MaxValue, 0);
return FlashWindowEx(ref fi);
}
return false;
}
/// Flash the specified Window (form) for the specified number of times
public static bool Flash(System.Windows.Forms.Form form, uint count)
{
if (Win2000OrLater)
{
FLASHWINFO fi = Create_FLASHWINFO(form.Handle, FLASHW_ALL, count, 0);
return FlashWindowEx(ref fi);
}
return false;
}
private static FLASHWINFO Create_FLASHWINFO(IntPtr handle, uint flags, uint count, uint timeout)
{
FLASHWINFO fi = new FLASHWINFO();
fi.cbSize = Convert.ToUInt32(Marshal.SizeOf(fi));
fi.hwnd = handle;
fi.dwFlags = flags;
fi.uCount = count;
fi.dwTimeout = timeout;
return fi;
}
/// helper methods
public static bool Tray(System.Windows.Forms.Form form)
{
if (Win2000OrLater)
{
FLASHWINFO fi = Create_FLASHWINFO(form.Handle, FLASHW_TRAY, uint.MaxValue, 0);
return FlashWindowEx(ref fi);
}
return false;
}
public static bool TrayAndWindow(System.Windows.Forms.Form form)
{
if (Win2000OrLater)
{
FLASHWINFO fi = Create_FLASHWINFO(form.Handle, FLASHW_ALL, uint.MaxValue, 0);
return FlashWindowEx(ref fi);
}
return false;
}
/// Stop Flashing the specified Window (form)
public static bool Stop(System.Windows.Forms.Form form)
{
if (Win2000OrLater)
{
FLASHWINFO fi = Create_FLASHWINFO(form.Handle, FLASHW_STOP, uint.MaxValue, 0);
return FlashWindowEx(ref fi);
}
return false;
}
/// A boolean value indicating whether the application is running on Windows 2000 or later.
private static bool Win2000OrLater
{
get { return System.Environment.OSVersion.Version.Major >= 5; }
}
}
Notes
https://docs.microsoft.com/en-us/windows/desktop/api/winuser/nf-winuser-flashwindowex
https://www.pinvoke.net/default.aspx/user32/flashwindowex.html?diff=y