Package is an abstract class that can be used to organize objects into a single entity of a defined physical format for portability and efficient access.

A ZIP file is the primary physical format for the Package. Other Package implementations might use other physical formats such as an XML document, a database, or Web service.

Like a file system, items contained in a Package are referenced in a hierarchical organization of folders and files.

Although Package is an abstract class, the ZipPackage derived class is used as default by the Package..::.Open method.

A PackagePart ("part") is the abstract class that represents an object that is stored in a Package.

A PackageRelationship ("relationship") defines an association between a source Package or PackagePart and a target object. A PackageRelationship can be one of two types, each of which can be one of two forms:

• Package-level relationship (created by Package..::.CreateRelationship)

  • Between a Package and a target part in the package.

  • Between a Package and a target resource outside the package.

• Part-level relationship (created by PackagePart..::.CreateRelationship)

  • Between a source PackagePart and another target part in the package.

  • Between a source PackagePart and a target resource outside the package.

The relationship's source Package or source PackagePart is considered the "owner" of the relationship. When the source object is deleted, all the relationships owned by the source object are also deleted. The process of creating or deleting a relationship does not physically change either the source or target objects in any way.

A PackageDigitalSignature ("digital signature") is a composition of parts and relationships representing a digital signature included with a Package. The digital signature identifies the originator and validates that the signed parts and relationships contained in the Package have not been modified.

Packages also support Digital Rights Management (DRM), which allows content elements in a Package to be encrypted with specific access rights granted to authorized users.

Based on the Package architecture, an XpsDocument is a package type designed for storing documents based on the open XML Paper Specification (XPS).

Windows Presentation Foundation (WPF) uses packages to store content, resources, and relationships for pages and documents using a standard ZIP file by default. As with any ZIP file, your application can use the System.IO.Packaging classes to store and optionally protect any type or number of data files in a single efficient-to-access container.

For more information, see the Open Packaging Conventions (OPC) specification, available for download at the XPS section of Windows Hardware Developer Central.

For a list of System.IO.Packaging related example programs, see the following:

• Packaging Samples

• Rights Management

• XPS Samples

Classes

---

	Class	Description
	EncryptedPackageEnvelope	Represents an OLE compound file that contains an encrypted package.
	Package	Represents a container that can store multiple data objects.
	PackageDigitalSignature	Represents a digital signature that is applied to a set of package parts and relationships.
	PackageDigitalSignatureManager	Provides a utility class for the creation and verification of digital signatures in a Package.
	PackagePart	Provides a base class for parts stored in a Package. This class is abstract.
	PackagePartCollection	Represents a collection of PackagePart objects.
	PackageProperties	Represents the core properties of a Package.
	PackageRelationship	Represents an association between a source Package or PackagePart, and a target object which can be a PackagePart or external resource.
	PackageRelationshipCollection	Represents a collection of PackageRelationship elements that are owned by a given PackagePart or the Package.
	PackageRelationshipSelector	Defines PackageRelationship criteria to select part-level or package-level relationships.
	PackageStore	Represents a collection of application-specific Package instances used in combination with PackWebRequest.
	PackUriHelper	Provides utility methods to compose and parse pack URI objects.
	PackWebRequest	Makes a request to an entire PackagePart or to a PackagePart in a package, identified by a pack URI.
	PackWebRequestFactory	Represents the class that is invoked when an instance of a pack URI PackWebRequest is created.
	PackWebResponse	Represents a response of a PackWebRequest.
	RightsManagementInformation	Represents Digital Rights Management (DRM) information that is stored in an EncryptedPackageEnvelope.
	SignatureVerificationEventArgs	Specifies the event args provided to the InvalidSignatureEventHandler.
	StorageInfo	Provides access and information for manipulating data stores in a Package.
	StreamInfo	Provides access and information for manipulating I/O streams within a Package.
	ZipPackage	Implements a derived subclass of the abstract Package base class—the ZipPackage class uses a ZIP archive as the container store. This class cannot be inherited.
	ZipPackagePart	Represents a part that is stored in a ZipPackage.

Delegates

---

	Delegate	Description
	InvalidSignatureEventHandler	Represents the method that handles the InvalidSignatureEvent that is raised when VerifySignatures detects an invalid signature.

Enumerations

---

	Enumeration	Description
	CertificateEmbeddingOption	Specifies the location where the X.509 certificate that is used in signing is stored.
	CompressionOption	Specifies the compression level for content that is stored in a PackagePart.
	EncryptionOption	Specifies the encryption option for parts in a Package.
	PackageRelationshipSelectorType	Specifies the type of selection criteria that is used to match and return PackageRelationship selections through a PackageRelationshipSelector.
	TargetMode	Specifies whether the target of a PackageRelationship is inside or outside the Package.
	VerifyResult	Specifies the result of a certificate or signature verification.