Clipboard

Symbian platform supports the concept of cut, copy and paste by providing +a clipboard. An application can copy data to the clipboard and the same data +can then be pasted in by the same application or by any other application.

The clipboard is a resource which is shared by all applications. An application +must, therefore, hold the clipboard for the minimum time possible.

Cut, copy and paste

The clipboard is encapsulated +by the CClipboard class. Applications use this class when +they place data on, or retrieve data from the clipboard.

It is implemented +as a direct file store. When the data is placed on the clipboard, it is stored +in the clipboard's store as a stream or a network of streams. Every data type +placed on the clipboard is identified by a UID. This allows a pasting application +to identify the required data.

It uses a stream dictionary to maintain +UID and stream ID pairs, and always makes the stream dictionary the root stream +of the store.

The essential features of the CClipboard class +are shown in the following diagram:

+ Clipboard class structure + +

Any type of data can be placed on the clipboard. When retrieving +data, applications check the UID in the stream dictionary to determine whether +there is any data relevant to them. The following diagram illustrates a typical +situation:

+ Clipboard store + +