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ComponentChangingEventArgs Class
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ComponentChangingEventArgs Class

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

For a list of all members of this type, see ComponentChangingEventArgs Members.

System.Object
   System.EventArgs
      System.ComponentModel.Design.ComponentChangingEventArgs

[Visual Basic]
<ComVisible(True)>
NotInheritable Public Class ComponentChangingEventArgs
   Inherits EventArgs
[C#]
[ComVisible(true)]
public sealed class ComponentChangingEventArgs : EventArgs
[C++]
[ComVisible(true)]
public __gc __sealed class ComponentChangingEventArgs : public
   EventArgs
[JScript]
public
   ComVisible(true)
class ComponentChangingEventArgs extends EventArgs

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Remarks

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.

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

Example

[Visual Basic, C#, C++] The following example demonstrates creating a ComponentChangingEventArgs.

[Visual Basic] 
' This example method creates a ComponentChangingEventArgs using the specified arguments.
' Typically, this type of event args is created by a design mode subsystem.  
Public Function CreateComponentChangingEventArgs(ByVal component As Object, ByVal member As MemberDescriptor) As ComponentChangingEventArgs
    Dim args As New ComponentChangingEventArgs(component, member)

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

    Return args
End Function

[C#] 
// 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;
}

[C++] 
// This example method creates a ComponentChangingEventArgs using the specified arguments.
// Typically, this type of event args is created by a design mode subsystem.
ComponentChangingEventArgs* CreateComponentChangingEventArgs(Object* component, MemberDescriptor* member)
{
    // The component that is about to change:       args.Component
    // The member that is about to change:          args.Member

    return new ComponentChangingEventArgs(component, member);
}

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Namespace: System.ComponentModel.Design

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

Assembly: System (in System.dll)

See Also

ComponentChangingEventArgs Members | System.ComponentModel.Design Namespace | ComponentChanging | ComponentChanged | ComponentChangingEventHandler | IComponentChangeService

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