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Referencing Properties by Namespace

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This topic lists the namespaces that are supported by PropertyAccessor, Table, and View and their children objects, and discusses referencing named properties.

Namespaces used by Outlook objects

The following table summarizes the namespaces and the Outlook objects that the namespaces support. Note that property references by namespaces are case-sensitive.

Namespaces Supported Outlook Objects
https://schemas.microsoft.com/mapi/proptag Outlook item objects, AddressEntry, AddressList, Attachment, ExchangeDistributionList, ExchangeUser, Folder, Recipient, and Store objects.
https://schemas.microsoft.com/mapi/id (Same as above)
https://schemas.microsoft.com/mapi/string (Same as above)
https://schemas.microsoft.com/exchange (Same as above)
urn:schemas-microsoft-com:office:office Outlook item objects
urn:schemas-microsoft-com:office:outlook Outlook item objects
DAV: Outlook item objects
urn:schemas:calendar Outlook item objects
urn:schemas:contacts Outlook item objects
urn:schemas:httpmail Outlook item objects
urn:schemas:mailheader Outlook item objects

Messaging Application Programming Interface (MAPI) namespaces

Many properties that Outlook supports are MAPI properties. The PropertyAccessor object supports three subnamespaces of the MAPI namespace: proptag, id, and string. Each of the following sections contains a description for the subnamespace, a description for the format to reference a property in that subnamespace, and a definition of the syntax as expressed in Augmented Backus-Naur Form (ABNF), that is specified in [RFC4234].

proptag namespace

This namespace is used to access properties in the MAPI namespace using the property tag of a property. It supports only properties in the MAPI property range (that is, properties with a property identifier below 0x8000). The following is the format to reference a property in this namespace:

https://schemas.microsoft.com/mapi/proptag/0xHHHHHHHH

HHHHHHHH represents a hexadecimal property tag value, with a unique property identifier in the higher-order 16 bits, and a property type in the lower-order 16 bits. Every MAPI property must have a property tag, regardless of whether the property is defined by MAPI, Outlook, or a service provider. The hexadecimal value must follow the prefix "0x".

Formally, references of properties in this namespace can be defined in ABNF as follows:

  proptag-specifier = "https://schemas.microsoft.com/mapi/proptag/x" property-id property-type 
  property-id = 4HEXDIG 
  property-type = 4HEXDIG

For example, the following represents the MAPI property PidTagSubject that Outlook exposes in its object model as Subject:

https://schemas.microsoft.com/mapi/proptag/0x0037001E

id namespace

This namespace is used to access properties in a namespace identified by the globally unique identifier (GUID) of the namespace, using the identifier of the property. The following is the format to reference a property in this namespace:

https://schemas.microsoft.com/mapi/id/{HHHHHHHH-HHHH-HHHH-HHHH-HHHHHHHHHHHH}/HHHHHHHH

{HHHHHHHH-HHHH-HHHH-HHHH-HHHHHHHHHHHH} represents the namespace GUID, and HHHHHHHH represents the property tag.

Formally, references of properties in this namespace can be defined in ABNF as follows:

  id-specifier = "https://schemas.microsoft.com/mapi/id/" property-set "/x" property-long-id 
property-set = "{" 8HEXDIG "-" 4HEXDIG "-" 4HEXDIG "-" 4HEXDIG "-" 12HEXDIG "}" 
property-long-id = 8HEXDIG

For example, the following represents the Outlook NoAging property:

https://schemas.microsoft.com/mapi/id/{00062008-0000-0000-C000-000000000046}/850E000B

string namespace

This namespace is used to access string-named properties in an identified namespace. The following is the format to reference a property in this namespace:

https://schemas.microsoft.com/mapi/string/{HHHHHHHH-HHHH-HHHH-HHHH-HHHHHHHHHHHH}/ name

{HHHHHHHH-HHHH-HHHH-HHHH-HHHHHHHHHHHH} represents the namespace GUID, and name is the local property name defined as a string.

Formally, references of properties in this namespace can be defined in ABNF as follows:

  string-specifier = "https://schemas.microsoft.com/mapi/string/" property-set "/" property-name 
property-set = "{" 8*HEXDIG "-" 4*HEXDIG "-" 4*HEXDIG "-" 4*HEXDIG "-" 12*HEXDIG "}" 
property-name = 1*CHAR

The following is an example that uses this namespace:

https://schemas.microsoft.com/mapi/string/{00020386-0000-0000-C000-000000000046}/content-class

Escaping rules apply to referencing named properties in the string namespace. When referencing a named property that has a string identifier (for example, Author, Company, and Title), if the property name contains a space, single quote, double quote, or percent character, you must use Universal Resource Locator (URL) escaping and represent such characters with the corresponding escape string as shown in the following table.

Character in Property Reference Escape String
Space character %20
Double quote %22
Single quote %27
Percent character %25

The following is an example of how you specify and get the value of a named property, Mom's "Gift", defined in the MAPI string namespace, by using the PropertyAccessor.GetProperty method:

  PropertyAccessor.GetProperty("https://schemas.microsoft.com/mapi/string/{00020329-0000-0000-C000-000000000046}/Mom%27s%20%22Gift%22")

Exchange namespace

The exchange namespace is used to access string-named Exchange properties. The following is the format to reference a property in this namespace:

https://schemas.microsoft.com/exchange/ name

name is the local property name defined as a string.

The following is an example of a property referenced by this namespace:

https://schemas.microsoft.com/exchange/readreceiptrequested

Office namespaces

The PropertyAccessor object supports two Office subnamespaces:

Office namespace

This namespace is used to access properties of the DocumentItem object. The following is the format to reference a property in this namespace:

urn:schemas-microsoft-com:office:office# name

name is the local property name defined as a string.

The following are some examples of referencing DocumentItem properties using the Office namespace:

  • urn:schemas-microsoft-com:office:office#Subject

  • urn:schemas-microsoft-com:office:office#Template

Outlook namespace

This namespace is used to access Outlook item-level properties. Similar to other namespaces that support property referencing, use this namespace to access Outlook properties that are not explicitly exposed in the object model. The following is the format to reference a property in this namespace:

urn:schemas-microsoft-com:office:outlook# name

name is the local property name defined as a string.

The following is an example of referencing an Outlook item-level property by using the Outlook namespace:

urn:schemas-microsoft-com:office:outlook#remotemessagesize

Distributed authoring and versioning (DAV) namespaces

DAV namespaces are used to access Outlook item-level properties. A property in a DAV namespace is scoped using a Uniform Resource Identifier (URI) namespace reference. The format is a concatenation of the namespace URI prefix and the local property name expressed in a string, with the namespace URI being either a Uniform Resource Name (URN) or Uniform Resource Locator (URL).

The following are the DAV namespaces that the PropertyAccessor object supports:

  • DAV:

  • urn:schemas:calendar

  • urn:schemas:contacts

  • urn:schemas:httpmail

  • urn:schemas:mailheader

These are some examples of properties being referenced by different DAV namespaces:

  • DAV:checkintime

  • urn:schemas:httpmail:subject

  • urn:schemas:mailheader:subject

See also

Support and feedback

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