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ComponentChangingEventArgs Class

Provides data for the ComponentChanging event. This class cannot be inherited.

Namespace: System.ComponentModel.Design
Assembly: System (in system.dll)

[ComVisibleAttribute(true)] 
public sealed class ComponentChangingEventArgs : EventArgs
/** @attribute ComVisibleAttribute(true) */ 
public final class ComponentChangingEventArgs extends EventArgs
ComVisibleAttribute(true) 
public final class ComponentChangingEventArgs extends EventArgs
Not applicable.

ComponentChangingEventArgs provides data about a ComponentChanging event. The ComponentChanging event notifies the IComponentChangeService and registered event handlers that a particular component in the current design document is about to be changed. This event provides a widely accessible method to prevent a component from changing.

A ComponentChanging event is raised before a component is changed. This event provides an opportunity for a designer to abort the change. Component designers typically raise the ComponentChanging event automatically. If a property cannot be changed, the method that handles the event can throw an exception. For example, if a designer file is checked into source code control, the handler of this event typically throws an exception if the user refuses to check out the file.

A ComponentChangingEventArgs provides the following information:

  • A Component property that indicates the component that is about to be modified.

  • A Member property that indicates the member that is about to be changed.

NoteNote:

The HostProtectionAttribute attribute applied to this class has the following Resources property value: SharedState. The HostProtectionAttribute does not affect desktop applications (which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser). For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes.

Notes to Inheritors: A compiler error occurs if this class is specified as the base class of another class.

The following example demonstrates creating a ComponentChangingEventArgs.

// This example method creates a ComponentChangingEventArgs using the specified arguments.
// Typically, this type of event args is created by a design mode subsystem.  
public ComponentChangingEventArgs CreateComponentChangingEventArgs(object component, MemberDescriptor member)
{
    ComponentChangingEventArgs args = new ComponentChangingEventArgs(component, member);

    // The component that is about to change:       args.Component
    // The member that is about to change:          args.Member

    return args;
}

// This example method creates a ComponentChangingEventArgs
// using the specified arguments.
// Typically, this type of event args is created by a design mode subsystem.
public ComponentChangingEventArgs CreateComponentChangingEventArgs(
    Object component, MemberDescriptor member)
{
    ComponentChangingEventArgs args = new 
        ComponentChangingEventArgs(component, member);
    // The component that is about to change:       args.Component
    // The member that is about to change:          args.Member
    return args;
} //CreateComponentChangingEventArgs

System.Object
   System.EventArgs
    System.ComponentModel.Design.ComponentChangingEventArgs
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0
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