ComponentChangedEventArgs Class

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


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

[<HostProtectionAttribute(SecurityAction.LinkDemand, SharedState = true)>]
[<PermissionSetAttribute(SecurityAction.LinkDemand, Name = "FullTrust")>]
type ComponentChangedEventArgs =  
        inherit EventArgs 

The ComponentChangedEventArgs type exposes the following members.

Public methodComponentChangedEventArgsInitializes a new instance of the ComponentChangedEventArgs class.

Public propertyComponentGets the component that was modified.
Public propertyMemberGets the member that has been changed.
Public propertyNewValueGets the new value of the changed member.
Public propertyOldValueGets the old value of the changed member.

Public methodEquals(Object)Determines whether the specified object is equal to the current object. (Inherited from Object.)
Public methodGetHashCodeServes as the default hash function. (Inherited from Object.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)

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.


The HostProtectionAttribute attribute applied to this type or member 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 ComponentChangedEventArgs.

No code example is currently available or this language may not be supported.

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

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