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AssemblyName Class

Describes an assembly's unique identity in full.

Namespace: System.Reflection
Assembly: mscorlib (in mscorlib.dll)

public sealed class AssemblyName : _AssemblyName, ICloneable, ISerializable, 
/** @attribute SerializableAttribute() */ 
/** @attribute ClassInterfaceAttribute(ClassInterfaceType.None) */ 
/** @attribute ComVisibleAttribute(true) */ 
public final class AssemblyName implements _AssemblyName, ICloneable, 
	ISerializable, IDeserializationCallback
public final class AssemblyName implements _AssemblyName, ICloneable, 
	ISerializable, IDeserializationCallback

The AssemblyName object contains information about an assembly, which you can use to bind to that assembly. An assembly's identity consists of the following:

  • simple name

  • version number

  • cryptographic key pair

  • supported culture

The simple name is typically the file name for the manifest file without its extension. The key pair includes a public and private key, used to create strong-name signatures for assemblies.

All compilers that support the common language runtime will emit the simple name of a nested class, and reflection constructs a mangled name when queried, in accordance with the following conventions.



Backslash (\)

Escape character.

Comma (,)

Precedes the Assembly name.

Plus sign (+)

Precedes a nested class.

For example, the fully qualified name for a class might look like this:


A "++" becomes "\+\+", and a "\" becomes "\\".

This qualified name can be persisted and later used to load the Type. To search for and load a Type, use GetType either with the type name only or with the assembly qualified type name. GetType with the type name only will look for the Type in the caller's assembly and then in the System assembly. GetType with the assembly qualified type name will look for the Type in any assembly.

A fully specified AssemblyName must have the name, culture, public key or public key token, major version, minor version, build number, and revision number parameters. The last four are packaged in the Version type.

To create a simple name, create an AssemblyName object using the default constructor and set the Name. The other properties are optional.

To create a full strong name, create an AssemblyName object using the default constructor and set the Name and KeyPair. The other properties are optional. Use SetPublicKey and SetPublicKeyToken to set the public key and the strong name. The strong name signing always uses the SHA1 hash algorithm.

To assure the correct construction of the names, use the following properties:

You can also get the name by using the /l option with the Global Assembly Cache Tool (Gacutil.exe)

For a partially specified strong name, create an AssemblyName object using the default constructor and set the name and public key. An assembly created using such an AssemblyName can be signed later using the Assembly Linker (Al.exe).

It is possible to specify a public key and a KeyPair with inconsistent values. This can be useful in developer scenarios. In this case, the public key retrieved with GetPublicKey specifies the correct public key, while the KeyPair specifies the public and private keys used during development. When the runtime detects a mismatch between the KeyPair and the public key, it looks up in the registry the correct key that matches the public key.

The format of the display name of an AssemblyName is a comma-delimited Unicode string that begins with the name, as follows:

Name <,Culture = CultureInfo> <,Version = Major.Minor.Build.Revision> <, StrongName> <,PublicKeyToken> '\0'

Name is the textual name of the assembly. CultureInfo is the RFC1766-format-defined culture. Major, Minor, Build, and Revision are the major version, minor version, build number, and revision number of the assembly. StrongName is the hexadecimal-encoded low-order 64 bits of the hash value of the public key generated using the SHA-1 hashing algorithm and the public key specified by SetPublicKey. PublicKeyToken is the hexadecimal-encoded public key specified by SetPublicKey.

Hexadecimal encoding is defined as the conversion of each byte of a binary object to two hexadecimal characters, progressing from least to most significant byte. Additional display values will be added as deemed necessary.

If the full public key is known, then PublicKey may be substituted for StrongName.

Also note that except for Name, which must come first, the lexical order of parameters is unimportant. However, any parameter (Version, Culture, StrongName or PublicKey) not specifically set is considered to be omitted, and the AssemblyName is then considered partial. When specifying partial information, Name parameters must be specified in the order described above.

When supplying a display name, the convention StrongName =null or PublicKey= null indicates that binding and matching against a simply named assembly is required. Additionally, the convention Culture= "" (double quote representing an empty string) indicates matching against the default culture.

The following code example shows an AssemblyName for a simply named assembly with default culture.


The following code example shows a fully specified reference for a strongly named assembly with culture "en".

com.microsoft.crypto, Culture=en, PublicKeyToken=a5d015c7d5a0b012, Version=

This example shows how to use various reflection classes to analyze the metadata contained in an assembly.

Imports System
Imports System.Reflection

Module Module1

    Sub Main()
        ' This variable holds the amount of indenting that 
        ' should be used when displaying each line of information.
        Dim indent As Int32 = 0
        ' Display information about the EXE assembly.
        Dim a As [Assembly] = System.Reflection.Assembly.GetExecutingAssembly()
        Display(indent, "Assembly identity={0}", a.FullName)
        Display(indent + 1, "Codebase={0}", a.CodeBase)

        ' Display the set of assemblies our assemblies references.
        Dim an As AssemblyName
        Display(indent, "Referenced assemblies:")
        For Each an In a.GetReferencedAssemblies()
            Display(indent + 1, "Name={0}, Version={1}, Culture={2}, PublicKey token={3}", _
                an.Name, an.Version, an.CultureInfo.Name, BitConverter.ToString(an.GetPublicKeyToken))
        Display(indent, "")

        ' Display information about each assembly loading into this AppDomain.
        For Each a In AppDomain.CurrentDomain.GetAssemblies()
            Display(indent, "Assembly: {0}", a)

            ' Display information about each module of this assembly.
            Dim m As [Module]
            For Each m In a.GetModules(True)
                Display(indent + 1, "Module: {0}", m.Name)

            ' Display information about each type exported from this assembly.
            Dim t As Type
            indent += 1
            For Each t In a.GetExportedTypes()
                Display(0, "")
                Display(indent, "Type: {0}", t)

                ' For each type, show its members & their custom attributes.
                Dim mi As MemberInfo
                indent += 1
                For Each mi In t.GetMembers()
                    Display(indent, "Member: {0}", mi.Name)
                    DisplayAttributes(indent, mi)

                    ' If the member is a method, display information about its parameters.
                    Dim pi As ParameterInfo
                    If mi.MemberType = MemberTypes.Method Then
                        For Each pi In CType(mi, MethodInfo).GetParameters()
                            Display(indent + 1, "Parameter: Type={0}, Name={1}", pi.ParameterType, pi.Name)
                    End If

                    ' If the member is a property, display information about the property's accessor methods.
                    If mi.MemberType = MemberTypes.Property Then
                        Dim am As MethodInfo
                        For Each am In CType(mi, PropertyInfo).GetAccessors()
                            Display(indent + 1, "Accessor method: {0}", am)
                    End If
                indent -= 1
            indent -= 1
    End Sub

    ' Displays the custom attributes applied to the specified member.
    Sub DisplayAttributes(ByVal indent As Int32, ByVal mi As MemberInfo)
        ' Get the set of custom attributes; if none exist, just return.
        Dim attrs() As Object = mi.GetCustomAttributes(False)
        If attrs.Length = 0 Then Return

        ' Display the custom attributes applied to this member.
        Display(indent + 1, "Attributes:")
        Dim o As Object
        For Each o In attrs
            Display(indent + 2, "{0}", o.ToString())
    End Sub

    ' Display a formatted string indented by the specified amount.
    Sub Display(ByVal indent As Int32, ByVal format As String, ByVal ParamArray params() As Object)
        Console.Write(New String(" "c, indent * 2))
        Console.WriteLine(format, params)
    End Sub
End Module

'The output shown below is abbreviated.
'Assembly identity=Reflection, Version=, Culture=neutral, PublicKeyToken=null
'  Codebase=file:///C:/Reflection.exe
'Referenced assemblies:
'  Name=mscorlib, Version=1.0.5000.0, Culture=, PublicKey token=B7-7A-5C-56-19-34-E0-89
'  Name=Microsoft.VisualBasic, Version=7.0.5000.0, Culture=, PublicKey token=B0-3F-5F-7F-11-D5-0A-3A
'Assembly: mscorlib, Version=1.0.5000.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
'  Module: mscorlib.dll
'  Module: prc.nlp
'  Module: prcp.nlp
'  Module: ksc.nlp
'  Module: ctype.nlp
'  Module: xjis.nlp
'  Module: bopomofo.nlp
'  Module: culture.nlp
'  Module: region.nlp
'  Module: sortkey.nlp
'  Module: charinfo.nlp
'  Module: big5.nlp
'  Module: sorttbls.nlp
'  Module: l_intl.nlp
'  Module: l_except.nlp
'  Type: System.Object
'    Member: GetHashCode
'    Member: Equals
'      Parameter: Type=System.Object, Name=obj
'    Member: ToString
'    Member: Equals
'      Parameter: Type=System.Object, Name=objA
'      Parameter: Type=System.Object, Name=objB
'    Member: ReferenceEquals
'      Parameter: Type=System.Object, Name=objA
'      Parameter: Type=System.Object, Name=objB
'    Member: GetType
'    Member: .ctor
'  Type: System.ICloneable
'    Member: Clone
'  Type: System.Collections.IEnumerable
'    Member: GetEnumerator
'      Attributes:
'        System.Runtime.InteropServices.DispIdAttribute
'  Type: System.Collections.ICollection
'    Member: get_IsSynchronized
'    Member: get_SyncRoot
'    Member: get_Count
'    Member: CopyTo
'      Parameter: Type=System.Array, Name=array
'      Parameter: Type=System.Int32, Name=index
'    Member: Count
'      Accessor method: Int32 get_Count()
'    Member: SyncRoot
'      Accessor method: System.Object get_SyncRoot()
'    Member: IsSynchronized
'      Accessor method: Boolean get_IsSynchronized()

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0
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