windows-server-2003/com/oleutest/simpdnd

Simple Drag and Drop Sample

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This sample demonstrates an implementation of OLE 2 drag and drop. It allows

drag and drop operations between two instances of the sample application.

For information on compiling and building the sample, see the makefile in

this directory.





Simple Drag and Drop Objects Overview :

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Simple Drag and Drop consists of three main objects. The top level is

CSimpleApp, under which is CSimpleDoc, and the innermost level is CSimpleSite.

CSimpleApp is used to hold all the main window information. (eg. handle to

the main window, handles to the main, edit, and help menus and the application

instance) CSimpleApp always exists as long as the simple drag and drop

application is alive.



The next level object is CSimpleDoc object. It is instantiated when a new

document is created. It enables and disables the menu items in the main menu.

Since simple drag and drop is a single document interface application, the

user is only allowed to insert one object into the document. It is

necessary to disable certain items from the main menu to avoid incorrect

selection. It also registers the window for drag and drop and manipulates

the clipboard operations, such as copy to the clipboard, flush the clipboard.

It demonstrates the implementates of two OLE interfaces in its nested classes,

IDropSource and IDropTarget. These two interfaces are implemented as

CDropSource and CDropTarget respectively.



The CSimpleDoc object instantiates two different objects based on the user

selection from the main menu. The CSimpleSite object is instantiated if the

user chooses to insert a new object into the document. CSimpleSite

demonstrates the implementation of IAdviseSink and IOleClientSite through its

nested classes. These two interfaces are implemented as CAdviseSink and

COleClientSite accordingly. CSimpleSite manipulates the storage handling and

acts as a client site to communicate to a remote server. Such server can be

an executable server or a dll server. The CDataXferObj object is instantiated

when the user chooses to copy the existing object from the current document.

it is required to copy an object to the clipboard. CDataXferObj demonstrates

the IDataObject interface implementation and performs data transfer

operations.