System.ComponentModel.Component Class

Summary

Provides the base implementation for the IComponent interface and enables object-sharing between applications.

C# Syntax:

public class Component : MarshalByRefObject, IComponent, IDisposable

Component is the base class for all components in the common language runtime which marshal by reference. Component is remotable and derives from MarshalByRefObject. Component provides an implementation of IComponent. The MarshalByValueComponent provides an implementation of IComponent which marshals by value.

You can host a Component in any object that implements the IContainer interface, and can query and get services from its container. The container creates an ISite for each Component it contains. The container uses the site to manage the Component and is used by the Component to communicate with its container.

It is recommended that a Component release resources explicitly by calls to its Component.Dispose method, without waiting for automatic memory management through an implicit call to Object.Finalize. When a Container is disposed, all components within the Container are also disposed.

System.ComponentModel Namespace | IComponent | IContainer | Container | ISite

System.ComponentModel.Component Member List:

Public Constructors

ctor #1

Default constructor. This constructor is called by derived class constructors to initialize state in this type.

Public Properties

Container	Read-only Gets the IContainer that contains the Component.
Site	Read-write Gets or sets the ISite of the Component.

Public Methods

CreateObjRef (inherited from System.MarshalByRefObject)	See base class member description: System.MarshalByRefObject.CreateObjRef Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object.
Dispose	Overloaded: Dispose() Releases all resources used by the Component.
Equals (inherited from System.Object)	See base class member description: System.Object.Equals Derived from System.Object, the primary base class for all objects.
GetHashCode (inherited from System.Object)	See base class member description: System.Object.GetHashCode Derived from System.Object, the primary base class for all objects.
GetLifetimeService (inherited from System.MarshalByRefObject)	See base class member description: System.MarshalByRefObject.GetLifetimeService Retrieves the current lifetime service object that controls the lifetime policy for this instance.
GetType (inherited from System.Object)	See base class member description: System.Object.GetType Derived from System.Object, the primary base class for all objects.
InitializeLifetimeService (inherited from System.MarshalByRefObject)	See base class member description: System.MarshalByRefObject.InitializeLifetimeService Obtains a lifetime service object to control the lifetime policy for this instance.
ToString	Overridden: Returns a String containing the name of the Component, if any. This method should not be overridden. For internal use only.

Public Events

Disposed

Adds an event handler to listen to the Component.Disposed event on the component.

Protected Properties

DesignMode	Read-only Gets a value that indicates whether the Component is currently in design mode.
Events	Read-only Gets the list of event handlers that are attached to this Component.

Protected Methods

Dispose	Overloaded: Dispose(bool disposing) Releases the unmanaged resources used by the Component and optionally releases the managed resources.
Finalize	Overridden:
GetService	Returns an object that represents a service provided by the Component or by its Container.
MemberwiseClone (inherited from System.Object)	See base class member description: System.Object.MemberwiseClone Derived from System.Object, the primary base class for all objects.

Hierarchy:

• System.Object
• System.MarshalByRefObject
• System.ComponentModel.Component
  • System.CodeDom.Compiler.CodeDomProvider
  • System.Diagnostics.Process
  • System.Net.WebClient
  • System.Runtime.Remoting.Services.RemotingClientProxy

System.ComponentModel.Component Member Details

Summary:

Default constructor. This constructor is called by derived class constructors to initialize state in this type.

C# Syntax:

public Component();

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Summary

Gets the IContainer that contains the Component.

C# Syntax:

public IContainer Container {get;}

The components in a container are tracked in a first-in, first-out list, which also defines the order of the components within the container. The last component added is the last component in the list.

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Summary

Gets a value that indicates whether the Component is currently in design mode.

C# Syntax:

protected bool DesignMode {get;}

The design mode indicator is stored in the ISite; therefore, if the Component does not have an ISite associated with it, this property is always false.

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Summary

Gets the list of event handlers that are attached to this Component.

C# Syntax:

protected EventHandlerList Events {get;}

For more information about handling events, see the conceptual topic at MSDN: eventsoverview.

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Summary

Gets or sets the ISite of the Component.

C# Syntax:

public virtual ISite Site {get; set;}

Implements:

IComponent.Site

A Component will have an ISite if it has been added to an IContainer and the IContainer assigns an ISite to it. The IContainer is responsible to assign the ISite to the Component. Changing the value of the component's ISite does not necessarily change the name of the site the Component is assigned to. It is strongly suggested that the setting of the Component.Site property only be done by an IContainer.

The property value is null if the Component is removed from its IContainer. Assigning null to this property does not necessarily remove the Component from the IContainer.

A Component might or might not have a name. If a Component is given a name, the name must be unique among other Component objects within its IContainer. The ISite stores the name of the Component; therefore, you can only name a Component if it has an ISite associated with it.

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Inherited
See base class member description: System.MarshalByRefObject.CreateObjRef

Summary

Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object.

C# Syntax:

public virtual ObjRef CreateObjRef(    Type requestedType );

requestedType

The Type of the object that the new ObjRef will reference.

Return Value:

Information required to generate a proxy.

Exceptions

Exception Type	Condition
RemotingException	This instance is not a valid remoting object.

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Summary

Releases all resources used by the Component.

C# Syntax:

public void Dispose();

Implements:

IDisposable.Dispose

Calling Component.Dispose allows the resources used by the Component to be reallocated for other purposes. For more information about Component.Dispose, see the conceptual topic at MSDN: cleaningupunmanagedresources.

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Summary

Releases the unmanaged resources used by the Component and optionally releases the managed resources.

C# Syntax:

protected virtual void Dispose(    bool disposing );

disposing

true to release both managed and unmanaged resources; false to release only unmanaged resources.

This method is called by the public Dispose method and the Object.Finalize method.Dispose() invokes the protected Dispose(Boolean) method with the disposing parameter set to true. Object.Finalize invokes Dispose with disposing set to false.

When the disposing parameter is true, this method releases all resources held by any managed objects that this Component references. This method invokes the Dispose() method of each referenced object.

Notes to inheritors: Dispose can be called multiple times by other objects. When overriding Dispose(Boolean), be careful not to reference objects that have been previously disposed of in an earlier call to Dispose. For more information about how to implement Dispose(Boolean), see the conceptual topic at MSDN: implementingdisposemethod.

For more information about Dispose and Object.Finalize, see the conceptual topic at MSDN: cleaningupunmanagedresources and the conceptual topic at MSDN: overridingfinalizemethod.

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Inherited
See base class member description: System.Object.Equals

C# Syntax:

public virtual bool Equals(    object obj );

For more information on members inherited from System.Object click on the link above.

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C# Syntax:

~Component();

Calls Component.Dispose with disposing set to false to free unmanaged resources.

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Inherited
See base class member description: System.Object.GetHashCode

C# Syntax:

public virtual int GetHashCode();

For more information on members inherited from System.Object click on the link above.

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Inherited
See base class member description: System.MarshalByRefObject.GetLifetimeService

Summary

Retrieves the current lifetime service object that controls the lifetime policy for this instance.

C# Syntax:

public object GetLifetimeService();

Return Value:

An object of type ILease used to control the lifetime policy for this instance.

For more information about lifetime services, see the LifetimeServices class.

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Summary

Returns an object that represents a service provided by the Component or by its Container.

C# Syntax:

protected virtual object GetService(    Type service );

service

A service provided by the Component.

Return Value:

An Object that represents a service provided by the Component.

This value is null if the Component does not provide the specified service.

This method can be overridden by a derived class.

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Inherited
See base class member description: System.Object.GetType

C# Syntax:

public Type GetType();

For more information on members inherited from System.Object click on the link above.

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Inherited
See base class member description: System.MarshalByRefObject.InitializeLifetimeService

Summary

Obtains a lifetime service object to control the lifetime policy for this instance.

C# Syntax:

public virtual object InitializeLifetimeService();

Return Value:

An object of type ILease used to control the lifetime policy for this instance. This is the current lifetime service object for this instance if one exists; otherwise, a new lifetime service object initialized to the value of the LifetimeServices.LeaseManagerPollTime property.

For more information about lifetime services, see the LifetimeServices class.

The following code example demonstrates creating a lease.

 public class MyClass : MarshalByRefObject
 {
   public override Object InitializeLifetimeService()
   {
     ILease lease = (ILease)base.InitializeLifetimeService();
     if (lease.CurrentState == LeaseState.Initial)
     {
          lease.InitialLeaseTime = TimeSpan.FromMinutes(1);
          lease.SponsorshipTimeout = TimeSpan.FromMinutes(2);
           lease.RenewOnCallTime = TimeSpan.FromSeconds(2);
     }
       return lease;
   }
 }

    

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Inherited
See base class member description: System.Object.MemberwiseClone

C# Syntax:

protected object MemberwiseClone();

For more information on members inherited from System.Object click on the link above.

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Summary

Returns a String containing the name of the Component, if any. This method should not be overridden. For internal use only.

This type supports the Shared Source CLI infrastructure and is not intended to be used directly from your code.

C# Syntax:

public override string ToString();

Return Value:

A String containing the name of the Component, if any.

null if the Component is unnamed.

A Component may or may not have a name. If a Component is given a name, the name is unique among other Component objects within its IContainer.

The ISite stores the Component 's name. A Component can only have a ISite if it has been added to an IContainer and the IContainer assigns an ISite to it.

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Summary

Adds an event handler to listen to the Component.Disposed event on the component.

C# Syntax:

public event EventHandler Disposed;

When you create a Component.Disposed delegate, you identify the method that handles the event. To associate the event with your event handler, add an instance of the delegate to the event. The event handler is called whenever the event occurs, unless you remove the delegate. For more information about the event handler delegates, see the conceptual topic at MSDN: eventsdelegates.

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