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ComponentChangedEventArgs Class

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

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

System.Object
   System.EventArgs
      System.ComponentModel.Design.ComponentChangedEventArgs

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

ComponentChangedEventArgs provides data for a ComponentChanged event. The ComponentChanged event notifies the IComponentChangeService and registered event handlers that a particular component in the currently active document has been changed.

A ComponentChangedEventArgs provides the following information:

  • A Component property that indicates the component that was modified.
  • A Member property that indicates the member that was changed.
  • A NewValue property that indicates the new value of the member.
  • An OldValue property that indicates the old value of the member.

Component designers typically raise the ComponentChanged event automatically when components are added, removed, or modified. A ComponentChanged event is not raised during form load and unload because changes at this time are expected. A component designer might raise the ComponentChanged event after it changes a property of the component; this ensures that the Properties window will display the updated property.

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 ComponentChangedEventArgs.

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

    ' The component that has changed:              args.Component
    ' The member of the component that changed:    args.Member
    ' The old value of the member:                 args.oldValue
    ' The new value of the member:                 args.newValue
    Return args
End Function

[C#] 
// This example method creates a ComponentChangedEventArgs using the specified arguments.
// Typically, this type of event args is created by a design mode subsystem.            
public ComponentChangedEventArgs CreateComponentChangedEventArgs(object component, MemberDescriptor member, object oldValue, object newValue)
{            
    // Creates a component changed event args with the specified arguments.
    ComponentChangedEventArgs args = new ComponentChangedEventArgs(component, member, oldValue, newValue);

    // The component that has changed:              args.Component
    // The member of the component that changed:    args.Member
    // The old value of the member:                 args.oldValue
    // The new value of the member:                 args.newValue

    return args;            
}

[C++] 
// This example method creates a ComponentChangedEventArgs using the specified arguments.
// Typically, this type of event args is created by a design mode subsystem.
ComponentChangedEventArgs* CreateComponentChangedEventArgs(Object* component, MemberDescriptor* member, Object* oldValue, Object* newValue)
{
    // Creates a component changed event args with the specified arguments.
    ComponentChangedEventArgs* args = new ComponentChangedEventArgs(component, member, oldValue, newValue);

    // The component that has changed:              args.Component
    // The member of the component that changed:    args.Member
    // The old value of the member:                 args.oldValue
    // The new value of the member:                 args.newValue

    return args;
}

[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

ComponentChangedEventArgs Members | System.ComponentModel.Design Namespace | ComponentChanged | ComponentChanging | ComponentChangedEventHandler | IComponentChangeService

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