以编程方式停用屏保

Question

我有一个ACEPC T6，有一个通过HDMI连接的7英寸液晶屏幕和一个USB触摸屏。
该系统通过USB串行链路与处理器板连接，处理器板读取各种传感器并将数据反馈给PC机。
PC端程序用VB编写。2019年净。一切正常，只有一个例外。

我使用屏幕保护程序在活动10分钟后清空屏幕，触摸屏幕会使一切恢复正常。

我的问题是，我有一个PIR传感器连接到处理器，它发送命令回PC。我的目标是模拟屏幕被触摸，显示被恢复，即当有人走进房间，显示返回。

我尝试了各种各样的选项，模拟鼠标效果，发送按键，但都无济于事。
如有任何帮助，不胜感激。

我应该说一下我用的是Windows 10 Pro。

Answer 1

你可能无法使用SendInput()或其他函数得到一个积极的结果，因为屏保运行在特殊桌面，命名为(猜猜是什么)Screen-saver.
你需要得到这个桌面的句句来积极地与它或它的Windows交互

您可以使用SystemParametersInfo函数，传递SPI_GETSCREENSAVERRUNNING要确定屏保当前是否处于活动状态，则调用OpenDesktop()获取桌面的句柄(使用其名称)，找到屏保窗口(屏保是标准可执行文件)并发布WM_CLOSE消息关闭它。

在这里，我使用EnumDesktopWindows来查找屏幕保护程序。
(屏保窗口应该是前景窗口)。
如果失败，我们可以尝试关闭桌面，调用CloseDesktop()。

处理屏保

如果你有一个通过串行端口或类似的东西接收命令的过程，验证这个过程是否在UI线程以外的线程中运行，以防你在这种情况下需要访问UI。

将此代码添加到程序中:它检查屏幕保护程序是否处于活动状态并尝试关闭它。
已经在Windows 10 (19H2)和Windows 7 SP1中进行了测试。
。. Net Framework 4.8 - VB。净v.15

注意:你的应用程序意味着作为一个64位进程运行。如果您在项目的Build选项中设置了Prefer 32-bit，则需要这样做取消选择它。

假设这个过程在UI线程中运行。Me.Activate()不是严格要求的，只能从UI线程中使用。如果你的代码运行在另一个线程上，请删除它。

Protected Sub SomeProcedure()
If NativeMethods.GetScreenSaverActiveState() Then
NativeMethods.TerminateScreenSaver()
Me.Activate()
End If
End Sub

NativeMethods类和辅助方法:

Imports System.Runtime.InteropServices
Imports System.Security.Permissions
Friend Class NativeMethods
Public Shared Sub TerminateScreenSaver()
Try
TerminateScreenSaverCore()
Catch wex As Win32Exception
MessageBox.Show(wex.Message)
End Try
End Sub
Public Shared Function GetScreenSaverActiveState() As Boolean
Dim scState As IntPtr = IntPtr.Zero
SystemParametersInfo(SPI_GETSCREENSAVERRUNNING, 0UI, scState, 0UI)
Return scState <> IntPtr.Zero
End Function
<UIPermission(SecurityAction.Demand, Action:=SecurityAction.Demand, Window:=UIPermissionWindow.AllWindows)>
Private Shared Sub TerminateScreenSaverCore()
Call New SecurityPermission(SecurityPermissionFlag.UnmanagedCode).Demand()
Dim hDesktop As IntPtr = OpenDesktop("Screen-saver", 0, False,
DesktopAccessRights.DESKTOP_READOBJECTS Or DesktopAccessRights.DESKTOP_WRITEOBJECTS)
If hDesktop <> IntPtr.Zero Then
If Not EnumDesktopWindows(hDesktop,
Function(hWnd, lp)
If IsWindowVisible(hWnd) Then CloseWindow(hWnd)
Return True
End Function, IntPtr.Zero) Then
If Not CloseDesktop(hDesktop) Then
CloseWindow(GetForegroundWindow())
End If
End If
End If
End Sub
Private Shared Sub CloseWindow(hWnd As IntPtr)
PostMessage(hWnd, WM_CLOSE, IntPtr.Zero, IntPtr.Zero)
End Sub
Private Const WM_CLOSE As Integer = &H10
Private Const SPI_GETSCREENSAVERRUNNING As UInteger = &H72
Public Enum DesktopAccessRights As Long
DESKTOP_CREATEMENU = &H4L
DESKTOP_CREATEWINDOW = &H2L
DESKTOP_ENUMERATE = &H40L
DESKTOP_HOOKCONTROL = &H8L
DESKTOP_JOURNALPLAYBACK = &H20L
DESKTOP_JOURNALRECORD = &H10L
DESKTOP_READOBJECTS = &H1L
DESKTOP_SWITCHDESKTOP = &H100L
DESKTOP_WRITEOBJECTS = &H80L
End Enum
Private Delegate Function EnumWindowsProc(hDesktop As IntPtr, lParam As IntPtr) As Boolean
<DllImport("user32.dll", CharSet:=CharSet.Unicode, SetLastError:=True)>
Private Shared Function OpenDesktop(
lpszDesktop As String,
dwFlags As UInteger,
<[In], MarshalAs(UnmanagedType.Bool)> fInherit As Boolean,
dwDesiredAccess As DesktopAccessRights) As IntPtr
End Function
<DllImport("user32.dll", CharSet:=CharSet.Unicode, SetLastError:=True)>
Private Shared Function CloseDesktop(hDesktop As IntPtr) As Boolean
End Function
<DllImport("user32.dll", CharSet:=CharSet.Unicode, SetLastError:=True)>
Private Shared Function EnumDesktopWindows(
hDesktop As IntPtr,
callback As EnumWindowsProc,
lParam As IntPtr) As Boolean
End Function
<DllImport("user32.dll", CharSet:=CharSet.Unicode, SetLastError:=True)>
Public Shared Function GetForegroundWindow() As IntPtr
End Function
<DllImport("user32.dll", CharSet:=CharSet.Unicode, SetLastError:=True)>
Private Shared Function IsWindowVisible(hWnd As IntPtr) As <MarshalAs(UnmanagedType.Bool)> Boolean
End Function
<DllImport("user32.dll", CharSet:=CharSet.Unicode, SetLastError:=True)>
Private Shared Function PostMessage(hWnd As IntPtr, msg As UInteger, wParam As IntPtr, lParam As IntPtr) As Boolean
End Function
<DllImport("user32.dll", CharSet:=CharSet.Auto, SetLastError:=True)>
Private Shared Function SystemParametersInfo(uiAction As UInteger, uiParam As UInteger, ByRef pvParam As IntPtr, fWinIni As UInteger) As Boolean
End Function
End Class

c#版本，以防万一:

using System.Runtime.InteropServices;
using System.Security.Permissions;
internal static class NativeMethods
{
public static void TerminateScreenSaver()
{
try {
TerminateScreenSaverCore();
}
catch(Win32Exception wex){
MessageBox.Show(wex.Message);
}
}
public static bool GetScreenSaverActiveState()
{
var scState = IntPtr.Zero;
SystemParametersInfo(SPI_GETSCREENSAVERRUNNING, 0U, ref scState, 0U);
return scState != IntPtr.Zero;
}
[UIPermission(SecurityAction.Demand, Action = SecurityAction.Demand, Window = UIPermissionWindow.AllWindows)]
private static void TerminateScreenSaverCore()
{
new SecurityPermission(SecurityPermissionFlag.UnmanagedCode).Demand();
IntPtr hDesktop = OpenDesktop("Screen-saver", 0, false, 
DesktopAccessRights.DESKTOP_READOBJECTS | DesktopAccessRights.DESKTOP_WRITEOBJECTS);
if (hDesktop != IntPtr.Zero) {
if (!EnumDesktopWindows(hDesktop, (hWnd, lp)=> {
if (IsWindowVisible(hWnd)) CloseWindow(hWnd);
return true;
}, IntPtr.Zero) || !CloseDesktop(hDesktop)) {
CloseWindow(GetForegroundWindow());
}
}
}
private static void CloseWindow(IntPtr hWnd)
{
PostMessage(hWnd, WM_CLOSE, IntPtr.Zero, IntPtr.Zero);
}
private const uint SPI_GETSCREENSAVERRUNNING = 0x0072;
private const int WM_CLOSE = 0x0010;
public enum DesktopAccessRights : long
{
DESKTOP_CREATEMENU = 0x0004L,        // Required to create a menu on the desktop.
DESKTOP_CREATEWINDOW = 0x0002L,      // Required to create a window on the desktop.
DESKTOP_ENUMERATE = 0x0040L,         // Required for the desktop to be enumerated.
DESKTOP_HOOKCONTROL = 0x0008L,       // Required to establish any of the window hooks.
DESKTOP_JOURNALPLAYBACK = 0x0020L,   // Required to perform journal playback on a desktop.
DESKTOP_JOURNALRECORD = 0x0010L,     // Required to perform journal recording on a desktop.
DESKTOP_READOBJECTS = 0x0001L,       // Required to read objects on the desktop.
DESKTOP_SWITCHDESKTOP = 0x0100L,     // Required to activate the desktop using the SwitchDesktop function.
DESKTOP_WRITEOBJECTS = 0x0080L       // Required to write objects on the desktop.
}
private delegate bool EnumWindowsProc(IntPtr hDesktop, IntPtr lParam);
[DllImport("user32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
private static extern IntPtr OpenDesktop(
string lpszDesktop, 
uint dwFlags, 
[In, MarshalAs(UnmanagedType.Bool)]bool fInherit, 
DesktopAccessRights dwDesiredAccess);
[DllImport("user32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
private static extern bool CloseDesktop(IntPtr hDesktop);
[DllImport("user32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
private static extern bool EnumDesktopWindows(IntPtr hDesktop, EnumWindowsProc callback, IntPtr lParam);
[DllImport("user32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
private static extern bool IsWindowVisible(IntPtr hWnd);
[DllImport("user32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
public static extern IntPtr GetForegroundWindow();
[DllImport("user32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
[DllImport("user32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
private static extern bool PostMessage(IntPtr hWnd, uint msg, IntPtr wParam, IntPtr lParam);
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern bool SystemParametersInfo(uint uiAction, uint uiParam, ref IntPtr pvParam, uint fWinIni);
}