///////////////////////////////////////////////////////////////////////////////
// Description: Gets the target part of a relationship with the 'Internal' target mode.
///////////////////////////////////////////////////////////////////////////////
private static void GetRelationshipTargetPart(IOpcPartSet partSet, // Set of the parts in the package.
IOpcRelationship relationship, // Relationship that targets the required part.
string expectedContentType, // Content type expected for the target part.
out IOpcPart targetPart // Recieves pointer to target part. Method may return a valid
// pointer even on failure, and the caller must always release if a non-default value is returned.
)
{
targetPart = null;
OPC_URI_TARGET_MODE targetMode = relationship.GetTargetMode();
if (targetMode != OPC_URI_TARGET_MODE.OPC_URI_TARGET_MODE_INTERNAL)
{
// The relationship's target is not a part.
var relationshipType = relationship.GetRelationshipType();
Console.Error.Write("Invalid music bundle package: relationship with type {0} must have Internal target mode.\n", relationshipType);
// Set the return code to an error.
throw new InvalidOperationException();
}
// Relationship's target is a part; the target mode is 'Internal'.
// Get the URI of the relationship source.
IOpcUri sourceUri = relationship.GetSourceUri();
// Get the URI of the relationship target.
IUri targetUri = relationship.GetTargetUri();
// Resolve the target URI to the part name of the target part.
IOpcPartUri targetPartUri = sourceUri.CombinePartUri(targetUri);
// Check that a part with the resolved part name exists in the part set.
var partExists = partSet.PartExists(targetPartUri);
if (!partExists)
{
// The part does not exist in the part set.
Console.Error.Write("Invalid music bundle package: the target part of relationship does not exist.\n");
// Set the return code to an error.
throw new InvalidOperationException();
}
// Get the part.
targetPart = partSet.GetPart(targetPartUri);
// Get the content type of the part.
var contentType = targetPart.GetContentType();
if (contentType != expectedContentType)
{
// Content type of the part did not match the expected content type.
Console.Error.Write("Invalid music bundle package: the target part does not have correct content type.\n");
// Set the return code to an error.
throw new InvalidOperationException();
}
}
///////////////////////////////////////////////////////////////////////////////
// Description: Gets the relationship of the specified type from a specified relationship set.
// Note: Method expects exactly one relationship of the specified type. This limitation is described in the Music Bundle Package
// specification--and is not imposed by the Packaging APIs or the OPC.
///////////////////////////////////////////////////////////////////////////////
private static void GetRelationshipByType(IOpcRelationshipSet relsSet, // Relationship set that contains the relationship.
string relationshipType, // The relationship type of the relationship.
out IOpcRelationship targetRelationship // Recieves the relationship. Method may return a valid
// pointer even on failure, and the caller must always release if a non-default value is returned.
)
{
targetRelationship = null;
HRESULT hr = HRESULT.S_OK;
// Get an enumerator of all relationships of the required type.
IOpcRelationshipEnumerator relsEnumerator = relsSet.GetEnumeratorForType(relationshipType);
// Enumerate through relationships, ensuring that there is exactly one relationship that has the specified type.
var count = 0;
while (hr.Succeeded && (hr = relsEnumerator.MoveNext(out var hasNext)).Succeeded && hasNext)
{
count++;
if (count > 1)
{
// There is more than one relationship of the specified type.
Console.Error.Write("Invalid music bundle package: cannot have more than 1 relationship with type: {0}.\n", relationshipType);
// Set the return code to an error.
hr = HRESULT.E_FAIL;
// An error was encountered; stop enumerating.
break;
}
if (hr.Succeeded)
{
// Get the relationship at the current position of the enumerator.
hr = relsEnumerator.GetCurrent(out targetRelationship);
}
}
if (hr.Succeeded)
{
if (count == 0)
{
// There were no relationships in the set that had the specified type.
Console.Error.Write("Invalid music bundle package: relationship with type {0} does not exist.\n", relationshipType);
throw new InvalidOperationException();
}
}
else
{
throw new InvalidOperationException();
}
}
