CDataPathProperty Class

项目
12/18/2017

The latest version of this topic can be found at CDataPathProperty Class.

Implements an OLE control property that can be loaded asynchronously.

Syntax

class CDataPathProperty : public CAsyncMonikerFile

Members

Public Constructors

Name	Description
CDataPathProperty::CDataPathProperty	Constructs a `CDataPathProperty` object.

Public Methods

Name	Description
CDataPathProperty::GetControl	Retrieves the asynchronous OLE control associated with the `CDataPathProperty` object.
CDataPathProperty::GetPath	Retrieves the pathname of the property.
CDataPathProperty::Open	Initiates loading of the asynchronous property for the associated ActiveX (OLE) control.
CDataPathProperty::ResetData	Calls `CAsyncMonikerFile::OnDataAvailable` to notify the container that the control properties have changed.
CDataPathProperty::SetControl	Sets the asynchronous ActiveX (OLE) control associated with the property.
CDataPathProperty::SetPath	Sets the pathname of the property.

Remarks

Asynchronous properties are loaded after synchronous initiation.

The class CDataPathProperty is derived from CAysncMonikerFile. To implement asynchronous properties in your OLE controls, derive a class from CDataPathProperty, and override OnDataAvailable.

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

Inheritance Hierarchy

CDataPathProperty

Requirements

Header: afxctl.h

CDataPathProperty::CDataPathProperty

Constructs a CDataPathProperty object.

CDataPathProperty(COleControl* pControl = NULL);  
CDataPathProperty(LPCTSTR lpszPath, COleControl* pControl = NULL);
```  
  
### Parameters  
 `pControl`  
 A pointer to the OLE control object to be associated with this `CDataPathProperty` 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. `CDataPathProperty` uses URLs, not filenames. If you want a `CDataPathProperty` 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`.  
  
##  <a name="cdatapathproperty__getcontrol"></a>  CDataPathProperty::GetControl  
 Call this member function to retrieve the `COleControl` object associated with the `CDataPathProperty` object.

COleControl* GetControl();

  
### Return Value  
 Returns a pointer to the OLE control associated with the `CDataPathProperty` object. **NULL** if not control is associated.  
  
##  <a name="cdatapathproperty__getpath"></a>  CDataPathProperty::GetPath  
 Call this member function to retrieve the path, set when the `CDataPathProperty` object was constructed, or specified in **Open**, or specified in a previous call to the `SetPath` member function.

CString GetPath() const;

  
### Return Value  
 Returns the pathname to the property itself. Can be empty if no path has been specified.  
  
##  <a name="cdatapathproperty__open"></a>  CDataPathProperty::Open  
 Call this member function to initiate loading of the asynchronous property for the associated control.

virtual BOOL Open( COleControl* pControl,
CFileException* pError = NULL);

virtual BOOL Open( LPCTSTR lpszPath,
COleControl* pControl, CFileException* pError = NULL);

virtual BOOL Open( LPCTSTR lpszPath,
CFileException* pError = NULL);

virtual BOOL Open(CFileException* pError = NULL);

  
### Parameters  
 `pControl`  
 A pointer to the OLE control object to be associated with this `CDataPathProperty` object.  
  
 `pError`  
 A pointer to a file exception. In the event of an error, will be set to the cause.  
  
 `lpszPath`  
 The path, which may be absolute or relative, used to create an asynchronous moniker that references the actual absolute location of the property. `CDataPathProperty` uses URLs, not filenames. If you want a `CDataPathProperty` object for a file, prepend `file://` to the path.  
  
### Return Value  
 Nonzero if successful; otherwise 0.  
  
### Remarks  
 The function attempts to obtain the `IBindHost` interface from the control.  
  
 Before calling **Open** without a path, the value for the property's path must be set. This can be done when the object is constructed, or by calling the `SetPath` member function.  
  
 Before calling **Open** without a control, an ActiveX control (formerly known as an OLE control) can be associated with the object. This can be done when the object is constructed, or by calling `SetControl`.  
  
 All overloads of [CAsyncMonikerFile::Open](../Topic/CAsyncMonikerFile%20Class.md#casyncmonikerfile__open) are also available from `CDataPathProperty`.  
  
##  <a name="cdatapathproperty__resetdata"></a>  CDataPathProperty::ResetData  
 Call this function to get `CAsyncMonikerFile::OnDataAvailable` to notify the container that the control properties have changed, and all the information loaded asynchronously is no longer useful.

virtual void ResetData();

  
### Remarks  
 Opening should be restarted. Derived classes can override this function for different defaults.  
  
##  <a name="cdatapathproperty__setcontrol"></a>  CDataPathProperty::SetControl  
 Call this member function to associate an asynchronous OLE control with the `CDataPathProperty` object.

void SetControl(COleControl* pControl);

  
### Parameters  
 `pControl`  
 A pointer to the asynchronous OLE control to be associated with the property.  
  
##  <a name="cdatapathproperty__setpath"></a>  CDataPathProperty::SetPath  
 Call this member function to set the pathname of the property.

void SetPath(LPCTSTR lpszPath);

  
### Parameters  
 `lpszPath`  
 A path, which may be absolute or relative, to the property being loaded asynchronously. `CDataPathProperty` uses URLs, not filenames. If you want a `CDataPathProperty` object for a file, prepend `file://` to the path.  
  
## See Also  
 [MFC Sample Image](../Topic/Visual%20C++%20Samples.md)   
 [CAsyncMonikerFile Class](../Topic/CAsyncMonikerFile%20Class.md)   
 [Hierarchy Chart](../Topic/Hierarchy%20Chart.md)   
 [CAsyncMonikerFile Class](../Topic/CAsyncMonikerFile%20Class.md)

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