SystemEvents.UserPreferenceChanging 事件

定义

命名空间:

Microsoft.Win32

程序集:

Microsoft.Win32.SystemEvents.dll

包:

Microsoft.Win32.SystemEvents v8.0.0

Source:

SystemEvents.cs

当用户首选项更改时发生。

public:
 static event Microsoft::Win32::UserPreferenceChangingEventHandler ^ UserPreferenceChanging;

public static event Microsoft.Win32.UserPreferenceChangingEventHandler? UserPreferenceChanging;

member this.UserPreferenceChanging : Microsoft.Win32.UserPreferenceChangingEventHandler 

Public Shared Custom Event UserPreferenceChanging As UserPreferenceChangingEventHandler 

事件类型

UserPreferenceChangingEventHandler

例外

InvalidOperationException

当前上下文不支持系统事件通知。 例如，服务器进程可能不支持全局系统事件通知。

ExternalException

创建系统事件窗口线程的尝试未成功。

示例

下面的代码示例演示如何监视事件 UserPreferenceChanging 。 此代码示例是为 SystemEvents 类提供的一个更大示例的一部分。

int main()
{
    // Set the SystemEvents class to receive event notification
    // when a user preference changes, the palette changes, or
    // when display settings change.
    SystemEvents::UserPreferenceChanging += gcnew
        UserPreferenceChangingEventHandler(
        SystemEvents_UserPreferenceChanging);
    SystemEvents::PaletteChanged += gcnew
        EventHandler(SystemEvents_PaletteChanged);
    SystemEvents::DisplaySettingsChanged += gcnew
        EventHandler(SystemEvents_DisplaySettingsChanged);

    // For demonstration purposes, this application sits idle
    // waiting for events.
    Console::WriteLine("This application is waiting for system events.");
    Console::WriteLine("Press <Enter> to terminate this application.");
    Console::ReadLine();
}

static void Main() 
{         
    // Set the SystemEvents class to receive event notification when a user 
    // preference changes, the palette changes, or when display settings change.
    SystemEvents.UserPreferenceChanging += new 
        UserPreferenceChangingEventHandler(SystemEvents_UserPreferenceChanging);
    SystemEvents.PaletteChanged += new 
        EventHandler(SystemEvents_PaletteChanged);
    SystemEvents.DisplaySettingsChanged += new 
        EventHandler(SystemEvents_DisplaySettingsChanged);        

    // For demonstration purposes, this application sits idle waiting for events.
    Console.WriteLine("This application is waiting for system events.");
    Console.WriteLine("Press <Enter> to terminate this application.");
    Console.ReadLine();
}

'Set the SystemEvents class to receive event notification 
'when a user preference changes, the palette changes, or 
'when display settings change.
AddHandler SystemEvents.UserPreferenceChanging, _
AddressOf SystemEvents_UserPreferenceChanging

AddHandler SystemEvents.PaletteChanged, _
AddressOf SystemEvents_PaletteChanged

AddHandler SystemEvents.DisplaySettingsChanged, _
AddressOf SystemEvents_DisplaySettingsChanged

注解

注意

仅当消息泵正在运行时，才会引发此事件。 在 Windows 服务中，除非使用隐藏窗体或已手动启动消息泵，否则不会引发此事件。 有关演示如何在 Windows 服务中使用隐藏窗体处理系统事件的代码示例，请参阅 SystemEvents 类。

注意

由于这是静态事件，因此必须在释放应用程序时分离事件处理程序，否则会导致内存泄漏。

另请参阅

• UserPreferenceChangingEventArgs
• UserPreferenceChangingEventHandler
• UserPreferenceCategory