Abstract: in a solution with many projects, it may be useful to extract constant information from the per-project AssemblyInfo.cs into a solution-wide SharedAssemblyInfo.cs file.

About Assembly Attributes

An assembly (.dll or .exe file) contains four types of data: (1) an assembly manifest, (2) an application manifest, (3) compiled code, (4) resources.

The assembly manifest contains assembly name and version, a directory of contained types and resources, and other meta information. It is automatically embedded into the assembly by the compiler.

Name, version, and meta information is provided by [assembly: AssemblyFoo(...)] attributes. They must appear as the first thing in the source file (except using and extern clauses).

Common assembly attributes include:

[assembly: AssemblyCompany("Company Name")]
[assembly: AssemblyConfiguration("Debug")]
[assembly: AssemblyCopyright("© 2020 Company Name")]
[assembly: AssemblyCulture("")] // only set on satellite assemblies
[assembly: AssemblyDescription("blah blah")]
[assembly: AssemblyFileVersion("")] // see below
[assembly: AssemblyInformationalVersion("1.2 Update 3")] // display version
[assembly: AssemblyProduct("ProSuite")]
[assembly: AssemblyTitle("Component")]
[assembly: AssemblyVersion("")] // used by the CLR (see below)

Showing Attributes

To see all assembly attributes use a tool like ILSpy or dotPeek. Some assembly attributes are shown by the File Properties dialog in Windows Explorer as indicated in this table:

Property Attribute
File description AssemblyTitle
File version AssemblyFileVersion
Product name AssemblyProduct
Product version AssemblyInformationalVersion
Copyright AssemblyCopyright
Legal trademarks AssemblyTrademark

Explorer will not show some of the properties if their attributes are missing or empty. The value of the AssemblyDescription and AssemblyConfiguration attributes appear to not be shown here.

Assembly Versions

There are three version attributes:

  • AssemblyVersion: for assembly referencing (used by the CLR, defaults to
  • AssemblyFileVersion: to differentiate files with the same AssemblyVersion (defaults to AssemblyVersion)
  • AssemblyInformationalVersion: for display purposes, an arbitrary string (defaults to AssemblyFileVersion)

For example, here are the version attributes from Microsoft’s mscorlib (the Multilanguage Standard Common Object Runtime Library, colloquially also the Microsoft Core Library):

[assembly: AssemblyVersion("")]
[assembly: AssemblyFileVersion("4.8.4180.0")]
[assembly: AssemblyInformationalVersion("4.8.4180.0")]

The AssemblyVersion is part of the assembly’s fully qualified name, as in System.Xml, Version=, Culture=neutral, PublicKeyToken=b77a5c561934e089. Therefore, changing the AssemblyVersion changes the assembly’s identity and breaks references (could be fixed with assembly binding redirection). The two other version attributes are ignored by the CLR and can be changed at will. Typically, the AssemblyFileVersion includes a build number, and AssemblyInformationalVersion is a human friendly string.

Side note: System.Version provides four integer components named Major.Minor.Build.Revision. You are free to use the four components in other ways, typically: Build as Patch and Revision as Build.

var v = new System.Version("");
System.Console.WriteLine("{0}.{1}.{2}.{3}", v.Major, v.Minor, v.Build, v.Revision);
// outputs


Visual Studio automatically creates an AssemblyInfo.cs file within projects to contain the AssemblyFoo attributes. It also provides a dialog window to set them graphically.

With .NET Core, this will be different, the AssemblyInfo.cs files gone.

Centralising shared attributes

Usually, much of the information in AssemblyInfo.cs is constant across the projects in a Visual Studio solution. This redundancy can be reduced by factoring the common attributes out into a solution-wide SharedAssemblyInfo.cs file (or any name you like) and then linking from each project to this shared file.

  1. Create solution-wide SharedAssemblyInfo.cs file and add globally shared assembly attributes.
  2. Link this shared file into each project’s Properties folder: Right click Properties / Add / Existing Item / Add As Link
  3. Remove duplicate attributes from the per-project AssemblyInfo.cs files.

In this case, the project’s Assembly Information dialog should not be used as properties would be added to the per-project AssemblyInfo.cs file, thus creating duplicate assembly attributes (a compile-time error).

In the project (.csproj) file, Add As Link creates a Compile element that refers to the real location, with a nested Link element that states the place within the project source tree:

<Compile Include="..\SharedAssemblyInfo.cs">

Alternatively, the globally constant assembly attributes can be updated through an MSBuild task at build-time. Both MSBuild Extension Pack and MSBuild Community Tasks provide tasks for this job, but both projects appear to be dormant.


  • Do fill in as many of the assembly attributes as possible; it will look more prefessional (for example in the Explorer’s File Properties dialog)

  • State AssemblyCopyright as © YYYY Owner not as Copyright (c) YYYY Owner.

  • Consider linking to a globally shared assembly info file (to avoid redundancy and simplify automated version bumping).

  • State [assembly:CLSCompliant(true)] only if the entire assembly is intended to be CLS compliant (so that compile-time warnings may remind you of your intention). The default is false. (The CLS is the common subset of all CLR languages, so that a CLS compliant assembly can be used by any other CLR language.)

  • Increment AssemblyVersion when a breaking change is made.
  • Increment AssemblyFileVersion on each build (automatically).
  • Set AssemblyInformationalVersion if it deviates from AssemblyFileVersion (to which it defaults). May be useful for a nicely “human readable” version indication along with the product name.

Example SharedAssemblyInfo.cs (solution-wide)

using System.Reflection;

[assembly: AssemblyProduct("ProSuite")]
[assembly: AssemblyCompany("")]
[assembly: AssemblyCopyright("© 2020 The ProSuite Authors")]
[assembly: AssemblyTrademark("")]

[assembly: AssemblyConfiguration("Debug")]
[assembly: AssemblyConfiguration("Release")]

[assembly: AssemblyVersion("")]
[assembly: AssemblyFileVersion("")]
[assembly: AssemblyInformationalVersion("1.2 patch 3")]

Example AssemblyInfo.cs (per-project)

using System;
using System.Reflection;
using System.Runtime.InteropServices;

[assembly: AssemblyTitle("ProSuite.Essentials")]
[assembly: AssemblyDescription("Coding essentials (assertions, attributes, etc.)")]
[assembly: AssemblyCulture("")] // blank if neutral, only set on satellites!

[assembly: ComVisible(false)] // set to true if access from COM required
[assembly: CLSCompliant(false)] // set to true if CLS compliance is intended

// This GUID is for the ID of the typelib if this project is exposed to COM:
[assembly: Guid("xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx")]