IAsyncOperation interface

Enables interfaces that are usually synchronous to function asynchronously.

Note  This interface has been renamed IDataObjectAsyncCapability.

 

Members

The IAsyncOperation interface inherits from the IUnknown interface. IAsyncOperation also has these types of members:

• Methods

Methods

The IAsyncOperation interface has these methods.

Method	Description
EndOperation	Notifies the data object that the asynchronous data extraction has ended.
GetAsyncMode	Called by a drop target to determine whether the data object supports asynchronous data extraction.
InOperation	Called by the drop source to determine whether the target is extracting data asynchronously.
SetAsyncMode	Called by a drop source to specify whether the data object supports asynchronous data extraction.
StartOperation	Called by a drop target to indicate that asynchronous data extraction is starting.

 

Remarks

IAsyncOperation is an optional interface that is implemented by a data object. It allows the drop target to negotiate with the drop source to extract data from the data object asynchronously.

This interface is primarily exported by the data objects used with drag-and-drop and Clipboard operations. Typically, such operations are synchronous. However, if data rendering will be time-consuming, IAsyncOperation can be used to allow data extraction to take place on a background thread. See the Dragging and Dropping Shell Objects Asynchronously section of Handling Shell Data Transfer Scenarios for a detailed discussion of how to use this interface.

Drop sources and targets use this interface when they wish to have a lengthy data extraction process handled by a background thread.

Requirements

Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Header	Shldisp.h
IDL	Shldisp.idl
DLL	Shell32.dll (version 5.0 or later)