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CCachedDataPathProperty Class

  • Bài viết

Implements an OLE control property transferred asynchronously and cached in a memory file.

Syntax

class CCachedDataPathProperty : public CDataPathProperty

Members

Public Constructors

Name Description
CCachedDataPathProperty::CCachedDataPathProperty Constructs a CCachedDataPathProperty object.

Public Data Members

Name Description
CCachedDataPathProperty::m_Cache CMemFile object in which to cache data.

Remarks

A memory file is stored in RAM rather than on disk and is useful for fast temporary transfers.

Along with CAysncMonikerFile and CDataPathProperty, CCachedDataPathProperty provides functionality for the use of asynchronous monikers in OLE controls. With CCachedDataPathProperty objects, you are able to transfer data asynchronously from a URL or file source and store it in a memory file via the m_Cache public variable. All the data is stored in the memory file, and there is no need to override OnDataAvailable unless you want to watch for notifications and respond. For example, if you are transferring a large .GIF file and want to notify your control that more data has arrived and it should redraw itself, override OnDataAvailable to make the notification.

The class CCachedDataPathProperty is derived from CDataPathProperty.

For more information about how to use asynchronous monikers and ActiveX controls in Internet applications, see the following topics:

Inheritance Hierarchy

CObject

CFile

COleStreamFile

CMonikerFile

CAsyncMonikerFile

CDataPathProperty

CCachedDataPathProperty

Requirements

Header: afxctl.h

CCachedDataPathProperty::CCachedDataPathProperty

Constructs a CCachedDataPathProperty object.

CCachedDataPathProperty(COleControl* pControl = NULL);

CCachedDataPathProperty(
    LPCTSTR lpszPath,
    COleControl* pControl = NULL);

Parameters

pControl
A pointer to the ActiveX control object to be associated with this CCachedDataPathProperty object.

lpszPath
The path, which may be absolute or relative, used to create an asynchronous moniker that references the actual absolute location of the property. CCachedDataPathProperty uses URLs, not filenames. If you want a CCachedDataPathProperty object for a file, prepend file:// to the path.

Remarks

The COleControl object pointed to by pControl is used by Open and retrieved by derived classes. If pControl is NULL, the control used with Open should be set with SetControl. If lpszPath is NULL, you can pass in the path through Open or set it with SetPath.

CCachedDataPathProperty::m_Cache

Contains the class name of the memory file into which data is cached.

CMemFile m_Cache;

Remarks

A memory file is stored in RAM rather than on disk.

See also

CDataPathProperty Class
Hierarchy Chart
CDataPathProperty Class