UserPreferenceChangingEventHandler 代理人

定義

代表將處理 UserPreferenceChanging 事件的方法。Represents the method that will handle the UserPreferenceChanging event.

public delegate void UserPreferenceChangingEventHandler(System::Object ^ sender, UserPreferenceChangingEventArgs ^ e);
public delegate void UserPreferenceChangingEventHandler(object sender, UserPreferenceChangingEventArgs e);
type UserPreferenceChangingEventHandler = delegate of obj * UserPreferenceChangingEventArgs -> unit
Public Delegate Sub UserPreferenceChangingEventHandler(sender As Object, e As UserPreferenceChangingEventArgs)

參數

sender
Object

事件的來源。The source of the event. SystemEvents 類別引發這個事件時,這個物件永遠都是 nullWhen this event is raised by the SystemEvents class, this object is always null.

e
UserPreferenceChangingEventArgs

UserPreferenceChangedEventArgs,其中包含事件資料。A UserPreferenceChangedEventArgs that contains the event data.

繼承
UserPreferenceChangingEventHandler

範例

下列程式碼範例示範如何使用 UserPreferenceChangingEventHandler 類型來監視 UserPreferenceChanging 事件。The following code example demonstrates how to use the UserPreferenceChangingEventHandler type to monitor the UserPreferenceChanging event. 這個程式碼範例是針對類別提供之較大範例的一部分 SystemEventsThis code example is part of a larger example provided for the SystemEvents class.

#using <System.dll>

using namespace System;
using namespace Microsoft::Win32;

// This method is called when a user preference changes.
void SystemEvents_UserPreferenceChanging(Object^ sender,
     UserPreferenceChangingEventArgs^ e)
 {
     Console::WriteLine("The user preference is changing. Category={0}",
         e->Category);
 }

// This method is called when the palette changes.
void SystemEvents_PaletteChanged(Object^ sender, EventArgs^ e)
{
    Console::WriteLine("The palette changed.");
}

// This method is called when the display settings change.
void SystemEvents_DisplaySettingsChanged(Object^ sender,
    EventArgs^ e)
{
    Console::WriteLine("The display settings changed.");
}

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();
}

// This code produces the following output.
//
//  This app is waiting for system events.
//  Press <Enter> to terminate this application.
//  Display Settings changed.
//  User preference is changing. Category=General
using System;
using Microsoft.Win32;

public sealed class App 
{
    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();
    }

    // This method is called when a user preference changes.
    static void SystemEvents_UserPreferenceChanging(object sender, UserPreferenceChangingEventArgs e) 
    {
        Console.WriteLine("The user preference is changing. Category={0}", e.Category);
    }

    // This method is called when the palette changes.
    static void SystemEvents_PaletteChanged(object sender, EventArgs e)
    {
        Console.WriteLine("The palette changed.");
    }

    // This method is called when the display settings change.
    static void SystemEvents_DisplaySettingsChanged(object sender, EventArgs e)
    {
        Console.WriteLine("The display settings changed.");
    }
}

// This code produces the following output.
// 
//  This app is waiting for system events.
//  Press <Enter> to terminate this application.
//  Display Settings changed.
//  User preference is changing. Category=General
Imports Microsoft.Win32
Imports System.Windows.Forms

Friend Class Form1
    Inherits System.Windows.Forms.Form


    Public Sub New()
        MyBase.New()

        'This call is required by the Windows Form Designer.
        InitializeComponent()

        '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

    End Sub

    'Form overrides dispose to clean up the component list.
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If (components IsNot Nothing) Then
                components.Dispose()
            End If
        End If
        MyBase.Dispose(disposing)
    End Sub


    Private components As System.ComponentModel.IContainer

    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()

        Me.SuspendLayout()

        '
        'Form1
        '
        Me.ClientSize = New System.Drawing.Size(648, 398)
        Me.Name = "Form1"
        Me.Text = "Form1"
        Me.ResumeLayout(False)

    End Sub


    ' This method is called when a user preference changes.
    Private Sub SystemEvents_UserPreferenceChanging( _
    ByVal sender As Object, _
    ByVal e As UserPreferenceChangingEventArgs)

        MessageBox.Show("UserPreferenceChanging: " & _
        e.Category.ToString())
    End Sub


    ' This method is called when the palette changes.
    Private Sub SystemEvents_PaletteChanged( _
    ByVal sender As Object, _
    ByVal e As EventArgs)

        MessageBox.Show("PaletteChanged")

    End Sub


    ' This method is called when the display settings change.
    Private Sub SystemEvents_DisplaySettingsChanged( _
    ByVal sender As Object, _
    ByVal e As EventArgs)

        MessageBox.Show("The display settings changed.")

    End Sub

End Class

備註

建立 UserPreferenceChangingEventHandler 委派時,必須識別處理事件的方法。When you create a UserPreferenceChangingEventHandler delegate, you identify the method that will handle the event. 若要將事件與事件處理方法產生關聯,請將委派的實例加入至事件。To associate the event with your event-handling method, add an instance of the delegate to the event. 除非您移除委派,否則會在事件發生時呼叫事件處理方法。The event-handling method is called whenever the event occurs, unless you remove the delegate. 如需事件處理常式委派的詳細資訊,請參閱處理和引發事件For more information about event-handler delegates, see Handling and Raising Events.

擴充方法

GetMethodInfo(Delegate)

取得表示特定委派所代表之方法的物件。Gets an object that represents the method represented by the specified delegate.

適用於

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