// Locate core properties part using the package relationship that points to it.
private PackagePart?GetPropertyPart()
{
// Find a package-wide relationship of type CoreDocumentPropertiesRelationshipType.
PackageRelationship?corePropertiesRelationship = GetCorePropertiesRelationship();
if (corePropertiesRelationship == null)
{
return(null);
}
// Retrieve the part referenced by its target URI.
if (corePropertiesRelationship.TargetMode != TargetMode.Internal)
{
throw new FileFormatException(SR.NoExternalTargetForMetadataRelationship);
}
PackagePart?propertiesPart = null;
Uri propertiesPartUri = PackUriHelper.ResolvePartUri(
PackUriHelper.PackageRootUri,
corePropertiesRelationship.TargetUri);
if (!_package.PartExists(propertiesPartUri))
{
throw new FileFormatException(SR.DanglingMetadataRelationship);
}
propertiesPart = _package.GetPart(propertiesPartUri);
if (!propertiesPart.ValidatedContentType.AreTypeAndSubTypeEqual(s_coreDocumentPropertiesContentType))
{
throw new FileFormatException(SR.WrongContentTypeForPropertyPart);
}
return(propertiesPart);
}
// Find a package-wide relationship of type CoreDocumentPropertiesRelationshipType.
private PackageRelationship?GetCorePropertiesRelationship()
{
PackageRelationship?propertiesPartRelationship = null;
foreach (PackageRelationship rel
in _package.GetRelationshipsByType(CoreDocumentPropertiesRelationshipType))
{
if (propertiesPartRelationship != null)
{
throw new FileFormatException(SR.MoreThanOneMetadataRelationships);
}
propertiesPartRelationship = rel;
}
return(propertiesPartRelationship);
}
/// <summary>
/// Retrieve a relationship per ID.
/// </summary>
/// <param name="id">The relationship ID.</param>
/// <returns>The relationship with ID 'id' or throw an exception if not found.</returns>
/// <exception cref="InvalidOperationException">If this part has been deleted</exception>
/// <exception cref="InvalidOperationException">If the parent package has been closed or disposed</exception>
/// <exception cref="IOException">If the package is write only, no information can be retrieved from it</exception>
/// <exception cref="ArgumentNullException">If parameter "id" is null</exception>
/// <exception cref="System.Xml.XmlException">If parameter "id" is not a valid Xsd Id</exception>
/// <exception cref="InvalidOperationException">If the requested relationship does not exist in the Package</exception>
public PackageRelationship GetRelationship(string id)
{
//All the validations for dispose and file access are done in the
//GetRelationshipHelper method.
PackageRelationship?returnedRelationship = GetRelationshipHelper(id);
if (returnedRelationship == null)
{
throw new InvalidOperationException(SR.PackagePartRelationshipDoesNotExist);
}
else
{
return(returnedRelationship);
}
}