# DispSink Sample: Handles Events Fired from a Singleton COM Server Through a Dispatch Interface

The DispSink sample demonstrates a singleton server object (an object that can have only one instance) that has its own dual interface and a dispatch interface used for firing off events.

The DispSink attributes sample is the attributed version of this sample.

Security Note
This sample code is provided to illustrate a concept and should not be used in applications or Web sites, as it may not illustrate the safest coding practices.

# Building and Running the Sample

#### To build and run this sample

1. Open the solution file DispSink.sln.

2. From the Build menu, click Build Solution.

3. Open two or more instances of the ActiveX Control Test Container and insert the client control, DispCtl, into each instance. See Testing Properties and Events with Test Container for information on how to access the test container.

4. Invoke the Connect method on all of the controls.

5. Invoke the Send method on one of the controls. Change the Parameter Type field of the Invoke Methods dialog box to VT_BSTR and then type any string into the Parameter Value box. Click the Invoke button. The string will be displayed in the center of all connected controls.

6. Invoke the Disconnect method on all controls prior to deleting them.

# How the Sample Works

The server is a singleton object that has its own dual interface as well as a dispatch interface used for firing off events. The server object receives data through its dual interface Send method and transmits it to all connected components through the Transfer event on its dispatch interface.

The client is an ActiveX control that contains a server object. The control responds to the Transfer event fired by the server object. It has a dual interface that has Connect, Send, and Disconnect methods. If the Transfer event is fired with a variant containing a BSTR, the string is displayed in the center of the control.

# Keywords

This sample uses the following keywords:

#import; CComAutoThreadModule; CComSimpleThreadAllocator; CoCreateInstance; DECLARE_CLASSFACTORY_AUTO_THREAD(); FireViewChange