IMAPIProp::OpenProperty

Article
08/28/2006

The OpenProperty method returns a pointer to an interface to be used to access a property.

Note Windows Mobile-based Messaging implements this method only for IAttach and IMessage interface objects.

Syntax

HRESULT OpenProperty (
  ULONG ulPropTag,
  LPCIID lpiid,
  ULONG ulInterfaceOptions,
  ULONG ulFlags,
  LPUNKNOWN FAR * lppUnk
);

Parameters

ulPropTag
[in] Property tag for the property to be accessed; cannot be zero. Both the identifier and the type must be included in the property tag.
lpiid
[in] Ignored.
ulInterfaceOptions
[in] Ignored.
ulFlags
[in] Bitmask of flags that controls access to the property. The following flag can be set:

MAPI_MODIFY

Requests read/write access to the property. The default access is read-only.
lppUnk
[out] Reference to the requested interface object to be used for property access.

Return Values

This method returns the standard values E_INVALIDARG, E_OUTOFMEMORY, E_UNEXPECTED, and E_FAIL, as well as the following:

S_OK
Indicates success.
MAPI_E_INTERFACE_NOT_SUPPORTED
The requested interface is not supported for this property.
MAPI_E_NO_ACCESS
The caller has insufficient permissions to access the property.
MAPI_E_NO_SUPPORT
The object cannot provide access to this property through the requested interface.
MAPI_E_NOT_FOUND
The requested property does not exist.
MAPI_E_INVALID_PARAMETER
The property type in the tag is set to PT_UNSPECIFIED.

Remarks

OpenProperty is an alternate to IMAPIProp::GetProps and IMAPIProp::SetProps. When either GetProps or SetProps fails because the property is too large or too complex, call OpenProperty. OpenProperty is commonly used to access properties of type PT_OBJECT.

If OpenProperty is called from an IAttach interface object, the property represented by ulPropTag can only equal PR_ATTACH_DATA_BIN.

In Windows Mobile-based Messaging, lppUnk always returns a reference to an IStream interface object. You are responsible for recasting *lppUnk to an IStream pointer. You must also use the returned IStream pointer to call its Release method when you have finished with it.

Do not use the IStream pointer that you receive to call either its Seek or SetSize method, unless you use an offset position or size variable. Also, do not rely on the value of the plibNewPosition output parameter returned from the Seek call.

If you call OpenProperty to access a property with the IStream interface, use only that interface to make changes to it. Do not attempt to update the property with any of the other IMAPIProp methods such as SetProps or DeleteProps.

Do not try to open a property with OpenProperty more than once. The results are undefined because they can vary from provider to provider.

If you need to modify the property to be opened, set the MAPI_MODIFY flag. If you are not sure whether the object supports the property but think it should, set the MAPI_MODIFY flags.

Requirements

Pocket PC: Pocket PC 2002 and later
Smartphone: Smartphone 2002 and later
OS Versions: Windows CE 3.0 and later
Header: mapidefs.h
Library: cemapi.lib