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Enables data transfer and notification of changes in data. Data transfer methods specify the format of the transferred data along with the medium through which the data is to be transferred. Optionally, the data can be rendered for a specific target device. In addition to methods for retrieving and storing data, the IDataObject interface specifies methods for enumerating available formats and managing connections to advisory sinks for handling change notifications.
The term data object is used to mean any object that supports an implementation of the IDataObject interface. Implementations vary, depending on what the data object is required to do; in some data objects, the implementation of certain methods not supported by the object could simply be the return of E_NOTIMPL. For example, some data objects do not allow callers to send them data. Other data objects do not support advisory connections and change notifications. However, for those data objects that do support change notifications, OLE provides an object called a data advise holder. An interface pointer to this holder is available through a call to the helper function CreateDataAdviseHolder. A data object can have multiple connections, each with its own set of attributes. The OLE data advise holder simplifies the task of managing these connections and sending the appropriate notifications.
When to implement
Implement the IDataObject interface if you are developing a container or server application that is capable of transferring data. For example, if your application allows its data to be pasted or dropped into another application, you must implement the IDataObject interface. OLE compound document object servers that support objects that can be embedded or linked must implement IDataObject.
OLE provides implementations in its default object handler and its cache.
When to use
Any object that can receive data calls the methods in the IDataObject interface.
When you call the data transfer methods in the IDataObject interface, you specify a format, a medium, and, optionally, a target device for which the data should be rendered. Objects, such as containers, that want to be notified through their advise sinks when the data in the data object changes call the IDataObject advisory methods to set up an advisory connection through which notifications can be sent.
Members
The IDataObject interface inherits from the IUnknown interface. IDataObject also has these types of members:
Methods
The IDataObject interface has these methods.
Method | Description |
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DAdvise |
Creates a connection between a data object and an advise sink so the advise sink can receive notifications of changes in the data object. |
DUnadvise |
Destroys a notification previously set up with the DAdvise method. |
EnumDAdvise |
Creates and returns a pointer to an object to enumerate the current advisory connections. |
EnumFormatEtc |
Creates an object to enumerate the formats supported by a data object. |
GetCanonicalFormatEtc |
Provides a potentially different but logically equivalent FORMATETC structure. |
GetData |
Called by a data consumer to obtain data from a source data object. |
GetDataHere |
Called by a data consumer to obtain data from a source data object. This method differs from the GetData method in that the caller must allocate and free the specified storage medium. |
QueryGetData |
Determines whether the data object is capable of rendering the data as specified. |
SetData |
Called by an object containing a data source to transfer data to the object that implements this method. |
Requirements
Minimum supported client |
Windows 2000 Professional [desktop apps | UWP apps] |
---|---|
Minimum supported server |
Windows 2000 Server [desktop apps | UWP apps] |
Header |
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IDL |
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IID |
IID_IDataObject is defined as 0000010e-0000-0000-C000-000000000046 |