| Platform SDK: MAPI |
The IMAPIProp::CopyTo method copies or moves all properties, except for specifically excluded properties.
See IMAPIProp : IUnknown.
HRESULT CopyTo( ULONG ciidExclude, LPCIID rgiidExclude, LPSPropTagArray lpExcludeProps, ULONG ulUIParam, LPMAPIPROGRESS lpProgress, LPCIID lpInterface, LPVOID lpDestObj, ULONG ulFlags, LPSPropProblemArray FAR * lppProblems );
The following values can be returned in the SPropProblemArray structure, but not as return values for CopyTo. These errors apply to a single property:
The IMAPIProp::CopyTo method by default copies or moves all of the current object's properties to a destination object. CopyTo is used when an object should be copied or moved exactly, with all or most of its properties intact.
Any subobjects in the source object are automatically included in the operation and copied or moved in their entirety. By default, CopyTo overwrites any properties in the destination object that match properties from the source object. If any of the copied or moved properties already exist in the destination object, the existing properties are overwritten by the new, unless the MAPI_NOREPLACE flag is set in the ulFlags parameter. Existing information in the destination object that is not overwritten is left untouched.
You can provide a full implementation of CopyTo or rely on the implementation that MAPI provides in its support object. If you want to use the MAPI implementation, call IMAPISupport::DoCopyTo. However, If you do delegate processing to DoCopyTo and you are passed the MAPI_DECLINE_OK flag, avoid the support call and return MAPI_E_DECLINE_COPY instead. You will be called with this flag by MAPI to avoid the possible recursion that can happen when copying folders.
Because the copy operation can be lengthy, you are encouraged to display a progress indicator. Use the IMAPIProgress implementation passed in the lpProgress parameter, if there is one. If lpProgress is NULL, call IMAPISupport::DoProgressDialog to use the MAPI implementation.
Do not attempt to set any known read-only properties in the destination object; return MAPI_E_NO_ACCESS instead.
The source and destination objects should use the same interfaces. Return MAPI_E_INVALID_PARAMETER if lpInterface is not set.
Return MAPI_E_INTERFACE_NOT_SUPPORTED if all known interfaces are excluded.
Do not set the MAPI_DECLINE_OK flag; it is used by MAPI in its calls to message store provider CopyTo implementations.
Because copy and move operations can take time, it is wise to request the display of a progress indicator by setting the MAPI_DIALOG flag. You can set the lpProgress parameter to your implementation of IMAPIProgress, if you have one, or to NULL. If lpProgress is NULL, CopyTo will use the default progress indicator provided by MAPI.
You can suppress the display of a progress indicator by not setting the MAPI_DIALOG flag. CopyTo will ignore the ulUIParam and lpProgress parameters and avoid displaying the indicator.
CopyTo can report global and individual errors, or errors that occur with one or more properties. These individual errors are placed in an SPropProblemArray structure. You can suppress error reporting at the property level by passing NULL for the property problem array structure parameter rather than a valid pointer.
If you want to receive information about errors, pass a valid SPropProblemArray structure pointer in the lppProblems parameter. When CopyTo returns S_OK, check for possible errors with individual properties in the structure. When CopyTo returns an error, no information is returned in the SPropProblemArray structure. Instead, call IMAPIProp::GetLastError to retrieve detailed error information.
If CopyTo returns S_OK, free the returned SPropProblemArray structure by calling the MAPIFreeBuffer function.
If you are copying properties that are unique to the source object type, you must be sure that the destination object is of the same type. CopyTo does not prevent you from associating properties that typically belong to one type of object with another type of object. It is up to you to copy properties that make sense for the destination object. For example, you should not copy message properties to an address book container.
To ensure that you are copying between objects of the same type, check that the source and destination object are the same type, either by comparing object pointers or calling IUnknown::QueryInterface. Set the interface identifier pointed to by lpInterface to the standard interface for the source object. Also, make sure that the object type — or PR_OBJECT_TYPE property — is the same for the two objects. For example, if you are copying from a message, set lpInterface to IID_IMessage and the PR_OBJECT_TYPE for both objects to MAPI_MESSAGE.
If an invalid pointer is passed in the lpDestObj parameter, the results are unpredictable.
Excluding properties on a CopyTo call can be useful. For example, some objects have properties that are specific to a single instance of the object, such as the date and time of message delivery. To avoid copying a message's delivery time when copying the message to a different folder, specify PR_MESSAGE_DELIVERY_TIME in the property tag exclude array. To exclude a message's recipient list, add the PR_MESSAGE_RECIPIENTS property to the exclude array. To exclude a message's attachments, add the PR_MESSAGE_ATTACHMENTS property to the array.
Similarly, prevent the copying or moving of a folder or address book container's hierarchy or contents table by including PR_CONTAINER_HIERARCHY or PR_CONTAINER_CONTENTS in the property tag exclude array.
To exclude properties from the copy or move operation, include their property tags in the lpExcludeProps parameter. If you pass the results of using the PROP_TAG macro to build a property tag from a specific identifier in the property tag array, all properties with that identifier will be excluded. For example, the following entry in the property tag array causes all properties with an identifier of 0x8002 to be excluded, regardless of type:
PROP_TAG(PT_LONG, 0x8002)
The PR_NULL property tag cannot be included in the lpExcludeProps array.
The usefulness of the CopyTo feature for excluding interfaces is perhaps not as obvious as the usefulness of excluding properties. You can exclude an interface when copying to an object that has no knowledge of a group of properties. For example, if you are copying properties from a folder to an attachment, the only properties that the attachment will be able to work with are the generic properties accessible with any IMAPIProp implementation. By excluding IMAPIFolder from the copy operation, the attachment will not receive any of the more specific folder properties.
When you use the rgiidExclude parameter to exclude an interface, it also excludes all interfaces derived from that interface. For example, excluding IMAPIContainer causes folders or address book containers to be excluded, depending on the type of provider. Do not exclude IMAPIProp or IUnknown because so many interfaces derive from them.
Ignore MAPI_E_COMPUTED errors returned in the SPropProblemArray structure in the lppProblems parameter.
IMAPIFolder::CopyMessages, IMAPIProp::GetLastError, SPropProblemArray, SPropTagArray