1
[DllImport("CoreDll.dll")]
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private static extern void SystemIdleTimerReset();
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4
private static int nDisableSleepCalls = 0;
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private static System.Threading.Timer preventSleepTimer = null;
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private static void PokeDeviceToKeepAwake(object extra)
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{
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try
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{
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SystemIdleTimerReset();
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}
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catch (Exception e)
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{
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// TODO
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}
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}
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/**//// <summary>
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/// 禁止设备自动关闭电源
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/// </summary>
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public static void DisableDeviceSleep()
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{
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nDisableSleepCalls++;
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if (nDisableSleepCalls == 1)
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{
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//Debug.Assert(preventSleepTimer == null);
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// 没隔30秒刷新一次计时器
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preventSleepTimer = new System.Threading.Timer(new System.Threading.TimerCallback(PokeDeviceToKeepAwake),
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null, 0, 30 * 1000);
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}
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}
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/**//// <summary>
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/// 允许设备自动关闭电源
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/// </summary>
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public static void EnableDeviceSleep()
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{
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nDisableSleepCalls--;
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if (nDisableSleepCalls == 0)
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{
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//Debug.Assert(preventSleepTimer != null);
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if (preventSleepTimer != null)
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{
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preventSleepTimer.Dispose();
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preventSleepTimer = null;
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}
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}
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}
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这样我们只要在同步前调用DisableDeviceSleep方法,在同步后调用EnableDeviceSleep就OK了, 在也不用担心用户PDA电源自动关闭引起同步失败了.
可是事情远比我们想象的要复杂, 大家都PDA的背光也会自动关闭, 你可以想象一用户在同步时候的情形, 他在等待漫长的同步过程时背光突然关闭了, 可是我们让他电源不断, 这时候他以为电源关闭了, 结果按下了电源键盘, 结果不用我说了吧.
背光我们同样要处理, 是否也是有个线程作为背光定时器内, 答案是肯定的, 不过为了强调我们研究的技术性, 背光我用修改WinCE注册表方式搞定. 通过查阅资料我找到了这四个注册表键:
[HKEY_CURRENT_USER\ControlPanel\Backlight\BatteryTimeout] 使用外接电源时PDA自动关闭背光时间
[HKEY_CURRENT_USER\ControlPanel\Backlight\BatteryTimeoutUnchecked] 禁止使用电池自动关闭时为选中的时间
[HKEY_CURRENT_USER\ControlPanel\Backlight\ACTimeoutUnchecked] 禁止使用外接电源自动关闭时为选中的时间
/**//// <summary>
/// 指示背光是否被设置
/// </summary>
private static int nBatteryTimeoutCalls = 0;
private static int nACTimeoutCalls = 0;
/**//// <summary>
/// 禁止背光自动关闭
/// </summary>
public static bool DisableBacklightOff()
{
OpenNETCF.Win32.RegistryKey key = null;
bool bIsSet = false;
try
{
key = OpenNETCF.Win32.Registry.CurrentUser.OpenSubKey(@"ControlPanel\Backlight\", true);
if(key != null)
{
string oldValue1 = String.Empty;
string oldValue2 = String.Empty;
oldValue1 = key.GetValue("BatteryTimeout").ToString();
oldValue2 = key.GetValue("ACTimeout").ToString();
if(oldValue1.Trim() != "0")
{
nBatteryTimeoutCalls++;
if(nBatteryTimeoutCalls == 1)
{
key.SetValue("BatteryTimeout", 0);
key.SetValue("BatteryTimeoutUnchecked", int.Parse(oldValue1));
bIsSet = true;
}
else
{
nBatteryTimeoutCalls--;
}
}
if(oldValue2.Trim() != "0")
{
nACTimeoutCalls++;
if(nACTimeoutCalls == 1)
{
key.SetValue("ACTimeout", 0);
key.SetValue("ACTimeoutUnchecked", int.Parse(oldValue2));
bIsSet = true;
}
else
{
nACTimeoutCalls--;
}
}
if(bIsSet)
{
IntPtr hBackLightEvent = CreateEvent(IntPtr.Zero, false, true, "BackLightChangeEvent");
if (hBackLightEvent != IntPtr.Zero)
{
EventModify(hBackLightEvent,3);
CloseHandle(hBackLightEvent);
}
}
}
return true;
}
catch
{
return false;
}
finally
{
if(key != null)
{
key.Dispose();
key = null;
}
}
}
/**//// <summary>
/// 允许背光自动关闭
/// </summary>
public static bool EnableBacklightOff()
{
OpenNETCF.Win32.RegistryKey key = null;
bool bIsSet = false;
try
{
key = OpenNETCF.Win32.Registry.CurrentUser.OpenSubKey(@"ControlPanel\Backlight\", true);
if(key != null)
{
string oldValue1 = String.Empty;
string oldValue2 = String.Empty;
oldValue1 = key.GetValue("BatteryTimeoutUnchecked").ToString();
oldValue2 = key.GetValue("ACTimeoutUnchecked").ToString();
if(oldValue1.Trim() != "0")
{
nBatteryTimeoutCalls--;
if(nBatteryTimeoutCalls == 0)
{
key.SetValue("BatteryTimeoutUnchecked", 0);
key.SetValue("BatteryTimeout", int.Parse(oldValue1));
bIsSet = true;
}
else
{
nBatteryTimeoutCalls++;
}
}
if(oldValue2.Trim() != "0")
{
nACTimeoutCalls--;
if(nACTimeoutCalls == 0)
{
key.SetValue("ACTimeoutUnchecked", 0);
key.SetValue("ACTimeout", int.Parse(oldValue2));
bIsSet = true;
}
else
{
nACTimeoutCalls++;
}
}
if(bIsSet)
{
IntPtr hBackLightEvent = CreateEvent(IntPtr.Zero, false, true, "BackLightChangeEvent");
if (hBackLightEvent != IntPtr.Zero)
{
EventModify(hBackLightEvent,3);
CloseHandle(hBackLightEvent);
}
}
}
return true;
}
catch
{
return false;
}
finally
{
if(key != null)
{
key.Dispose();
key = null;
}
}
}
OK! 问题解决.
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