How can I handle the code if power is being switched off?
There is a way in Pocket PC to detect the power status change through a specialized notification mechanism. Power notifications are requested through the RequestPowerNotifications function it instruct the OS to start sending the appropriate power notification message. Based on these messages the code can be handled if the power is being switched off on the device.
Look at the sample C# code:
public class PowerNotifications
{
IntPtr ptr = IntPtr.Zero;
Thread t = null;
bool done = false;
[DllImport("coredll.dll")]
private static extern IntPtr RequestPowerNotifications(IntPtr hMsgQ, uint Flags);
[DllImport("coredll.dll")]
private static extern uint WaitForSingleObject(IntPtr hHandle, int wait);
[DllImport("coredll.dll")]
private static extern IntPtr CreateMsgQueue(string name, ref MsgQOptions options);
[DllImport("coredll.dll")]
private static extern bool ReadMsgQueue(IntPtr hMsgQ, byte[] lpBuffer, uint cbBufSize, ref uint lpNumRead, int dwTimeout, ref uint pdwFlags);
public PowerNotifications()
{
MsgQOptions options = new MsgQOptions();
options.dwFlags = 0;
options.dwMaxMessages = 4;
options.cbMaxMessage = 256;
options.bReadAccess = true;
options.dwSize = (uint)System.Runtime.InteropServices.Marshal.SizeOf(options);
ptr = CreateMsgQueue("PowerNotify", ref options);
RequestPowerNotifications(ptr, 0xFFFFFFFF);
t = new Thread(new ThreadStart(DoWork));
t.Start();
}
public void stop()
{
done = true;
}
private void DoWork()
{
//buf is declared with 8bytes, since 1st 4bytes are used for Powername and 2nd 4bytes are used for the actual power state type
byte[] buf = new byte[8];
uint nRead = 0, flags = 0, res = 0;
try
Join the conversation! Your thoughts help the community grow.