Home > Articles > Programming > Windows Programming

This chapter is from the book

Assembly Names

Each assembly has a four-part name that uniquely identifies it. This four-part name consists of the friendly name, culture, developer, and version of the component. These names are stored in the assembly manifest of the assembly itself as well as all assemblies that reference it. The CLR uses the four-part assembly name to find the correct component at load time. The CLR provides programmatic access to assembly names via the System.Reflection.AssemblyName type, which is easily accessed via the System.Reflection.Assembly.GetName method.

The Name property of the assembly name typically corresponds to the underlying file name of the assembly manifest sans any file extension that may be in use. This is the only part of the assembly name that is not optional. In simple scenarios, the Name property is all that the CLR needs to locate the correct component at load time. When one builds an assembly, this part of the name is automatically selected by your compiler based on the target file name.

All assembly names have a four-part version number (Version) of the form Major.Minor.Build.Revision. If you do not set this version number explicitly, its default value will be The version number is set at build time, typically using a custom attribute in the source code. The System.Reflection.AssemblyVersion attribute accepts a variety of string formats, as shown in Table 2.3. When you specify the version number, the Major version number is mandatory. Any missing parts are assumed to be zero. At build time, the Revision can be specified as * (asterisk), and that causes the compiler to use the wall clock to produce a monotonically increasing revision number for each compilation. If an * is specified for the Build number, the number emitted into the assembly manifest is based on the number of days that have elapsed since February 1, 2000, ensuring that each day has its own unique build number but that a given build number will be applied only for a given 24-hour period. You cannot specify an * for the Major or Minor part of the version number. Later, this chapter discusses how the assembly loader and resolver use the Version of the assembly.

Table 2.3 Inside the AssemblyVersion













Where d is the number of days since Feb. 1, 2000, and s is the number of seconds since midnight /2

Assembly names can contain a CultureInfo attribute that identifies the spoken language and country code that the component has been developed for. Developers specify CultureInfo using the System.Reflection.AssemblyCulture attribute, which accepts a two-part string as specified by Internet Engineering Task Force (IETF) Request for Comments (RFC) 1766. The first part of the string identifies the spoken language using a two-character lowercase code. The (optional) second part of the string identifies the geographic region using a two-character uppercase code. The string "en-US" identifies U.S. English. Assemblies that contain a CultureInfo cannot contain code; rather, they must be resource-only assemblies (also known as satellite assemblies) that can contain only localized strings and other user-interface elements. Satellite assemblies allow a single DLL containing code to selectively load (and download) localized resources based on where they are deployed. Assemblies containing code (that is, the vast majority of assemblies) are said to be culture-neutral and have no culture identifier.

Finally, an assembly name can contain a public key that identifies the developer of the component. An assembly reference can use either the full 128-byte public key or the 8-byte public key token. The public key (token) is used to resolve file name collisions between organizations, allowing multiple utilities.dll components to coexist in memory and on disk provided that each one originates from a different organization, each of which is guaranteed to have a unique public key. The next section discusses public key management in detail.

Because assembly references occasionally must be entered by hand (for example, for use in configuration files), the CLR defines a standard format for writing four-part assembly names as strings. This format is known as the display name of the assembly. The display name of the assembly always begins with the simple Name of the assembly and is followed by an optional list of comma-delimited properties that correspond to the other three properties of the assembly name. If all four parts of the name are specified, the corresponding assembly reference is called a fully qualified reference. If one or more of the properties is missing, the reference is called a partially qualified reference.

Figure 2.5 shows a display name and the corresponding CLR attributes used to control each property. Note that if an assembly with no culture is desired, the display name must indicate this using Culture=neutral. Also, if an assembly with no public key is desired, the display name must indicate this using PublicKeyToken=null. Both of these are substantially different from a display name with no Culture or PublicKeyToken property. Simply omitting these properties from the display name results in a partially specified name that allows any Culture or PublicKeyToken to be matched.

Figure 5Figure 2.5: Fully Specified Assembly Names

In general, you should avoid using partially specified assembly names; otherwise, various parts of the CLR will work in unexpected (and unpleasant) ways. However, to deal with code that does not heed this warning, the CLR allows partial assembly names to be fully qualified in configuration files. For example, consider the following application configuration file:

     <asm:qualifyAssembly partialName="AcmeCorp.Code"

This configuration allows the following call to Assembly.Load:

Assembly assm = Assembly.Load("AcmeCorp.Code");

The preceding call behaves identically to a call such as this one:

Assembly assm = Assembly.Load("AcmeCorp.Code,"+

The partialName attribute must match the parameter to Assembly.Load completely; that is, each property specified in the call to Assembly.Load must also be present in the partialName attribute in the configuration file. Also, each property specified in the partialName attribute must be present in the call to Assembly.Load. Later, this chapter discusses how configuration files are located.

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information

To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.


Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.


If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information

Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.


This site is not directed to children under the age of 13.


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information

If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information

Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents

California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure

Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact

Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice

We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020