IOleObject::GetUserType

项目
06/30/2006

This method retrieves the user type name of an object for display in user interface elements such as menus, list boxes, and dialog boxes.

HRESULT GetUserType( 
  DWORD dwFormOfType, 
  LPOLESTR* pszUserType
);

Parameters

dwFormOfType
[in] Specifies the form of the user-type name to be presented to users. Valid values are obtained from the USERCLASSTYPE enumeration.
pszUserType
[out] Address of LPOLESTR pointer variable that receives a pointer to the user type string. The caller must free *pszUserType using the current IMalloccerefIMalloc instance. If an error occurs, the implementation must set *pszUserType to NULL.

Return Values

One of the values described in the following table is returned.

Value	Description
S_OK	The object's user-type name is successfully returned.
OLE_S_USEREG	Delegate to the default handler's implementation using the registry to provide the requested information.

Remarks

Containers call GetUserType in order to represent embedded objects in list boxes, menus, and dialog boxes by their normal, user-recognizable names. Examples include "Word Document", "Excel Chart", and "Paintbrush Object". The information returned by GetUserType is the user-readable equivalent of the binary class identifier returned by IOleObject::GetUserClassID.

To determine whether the platform supports this interface, see Determining Supported COM APIs.

Notes to Callers

The default handler's implementation of GetUserType uses the object's class identifier (the pClsid parameter returned by GetUserClassID) and the dwFormOfType parameter together as a key into the registry. If an entry is found that matches the key exactly, then the user type specified by that entry is returned. If only the CLSID part of the key matches, then the lowest-numbered entry available (usually the full name) is used. If the CLSID is not found, or there are no user types registered for the class, the user type currently found in the object's storage is used.

You should not cache the string returned from GetUserType. Instead, call this method each and every time the string is needed. This guarantees correct results when the embedded object is being converted from one type into another without the caller's knowledge. Calling this method is inexpensive because the default handler implements it using the registry.

Notes to Implementers

You can use the implementation provided by the default handler by returning OLE_S_USEREG as your application's implementation of this method. If the user type name is an empty string, the message "Unknown Object" is returned.

Requirements

OS Versions: Windows CE 2.0 and later.
Header: Oleidl.h, Oleidl.idl.
Link Library: Oleaut32.lib, Uuid.lib.

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