ComponentChangedEventHandler 委托

定义

public delegate void ComponentChangedEventHandler(System::Object ^ sender, ComponentChangedEventArgs ^ e);

public delegate void ComponentChangedEventHandler(object sender, ComponentChangedEventArgs e);

public delegate void ComponentChangedEventHandler(object? sender, ComponentChangedEventArgs e);

[System.Runtime.InteropServices.ComVisible(true)]
public delegate void ComponentChangedEventHandler(object sender, ComponentChangedEventArgs e);

type ComponentChangedEventHandler = delegate of obj * ComponentChangedEventArgs -> unit

[<System.Runtime.InteropServices.ComVisible(true)>]
type ComponentChangedEventHandler = delegate of obj * ComponentChangedEventArgs -> unit

Public Delegate Sub ComponentChangedEventHandler(sender As Object, e As ComponentChangedEventArgs)

参数

属性

ComVisibleAttribute

示例

此示例演示如何注册 ComponentChangedEventHandler 并处理 ComponentChanged 事件。

public:
   void LinkComponentChangedEvent( IComponentChangeService^ changeService )
   {
      // Registers an event handler for the ComponentChanged event.
      changeService->ComponentChanged += gcnew ComponentChangedEventHandler(
         this, &ComponentChangedEventHandlerExample::OnComponentChanged );
   }

private:
   void OnComponentChanged( Object^ sender, ComponentChangedEventArgs^ e )
   {
      // Displays changed component information on the console.
      Console::WriteLine( "Type of the component that has changed: " +
         e->Component->GetType()->FullName );
      Console::WriteLine( "Name of the member of the component that has changed: " +
         e->Member->Name );
      Console::WriteLine( "Old value of the member: " + e->OldValue );
      Console::WriteLine( "New value of the member: " + e->NewValue );
   }

public void LinkComponentChangedEvent(IComponentChangeService changeService)
{
    // Registers an event handler for the ComponentChanged event.
    changeService.ComponentChanged += new ComponentChangedEventHandler(this.OnComponentChanged);            
}

private void OnComponentChanged(object sender, ComponentChangedEventArgs e)
{
    // Displays changed component information on the console.
    Console.WriteLine("Type of the component that has changed: "+e.Component.GetType().FullName);      
    Console.WriteLine("Name of the member of the component that has changed: "+e.Member.Name);            
    Console.WriteLine("Old value of the member: "+e.OldValue.ToString());
    Console.WriteLine("New value of the member: "+e.NewValue.ToString());
}

Public Sub LinkComponentChangedEvent(ByVal changeService As IComponentChangeService)
    ' Registers an event handler for the ComponentChanged event.
    AddHandler changeService.ComponentChanged, AddressOf Me.OnComponentChanged
End Sub

Private Sub OnComponentChanged(ByVal sender As Object, ByVal e As ComponentChangedEventArgs)
    ' Displays changed component information on the console.            
    Console.WriteLine(("Type of the component that has changed: " + e.Component.GetType().FullName))
    Console.WriteLine(("Name of the member of the component that has changed: " + e.Member.Name))
    Console.WriteLine(("Old value of the member: " + e.OldValue.ToString()))
    Console.WriteLine(("New value of the member: " + e.NewValue.ToString()))
End Sub

注解

创建 ComponentChangedEventHandler 委托时，需要标识将处理该事件的方法。 若要将事件与事件处理程序关联，请将该委托的一个实例添加到事件中。 除非移除了该委托，否则每当发生该事件时就会调用事件处理程序。 有关事件处理程序委托的详细信息，请参阅 处理和引发事件。

ComponentChanged加载或卸载窗体期间不会发生事件，因为这些操作期间需要更改。

扩展方法

适用于

另请参阅

• ComponentChanged
• ComponentChanging
• ComponentChangedEventArgs
• IComponentChangeService