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AppDomain.DefineDynamicAssembly Method (AssemblyName, AssemblyBuilderAccess, IEnumerable(Of CustomAttributeBuilder))

Defines a dynamic assembly with the specified name, access mode, and custom attributes.

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

'Declaration
Public Function DefineDynamicAssembly ( _
	name As AssemblyName, _
	access As AssemblyBuilderAccess, _
	assemblyAttributes As IEnumerable(Of CustomAttributeBuilder) _
) As AssemblyBuilder

Parameters

name
Type: System.Reflection.AssemblyName

The unique identity of the dynamic assembly.

access
Type: System.Reflection.Emit.AssemblyBuilderAccess

The access mode for the dynamic assembly.

assemblyAttributes
Type: System.Collections.Generic.IEnumerable(Of CustomAttributeBuilder)

An enumerable list of attributes to be applied to the assembly, or Nothing if there are no attributes.

Return Value

Type: System.Reflection.Emit.AssemblyBuilder
A dynamic assembly with the specified name and features.

ExceptionCondition
ArgumentNullException

name is Nothing.

ArgumentException

The Name property of name is Nothing.

-or-

The Name property of name starts with white space, or contains a forward or backward slash.

AppDomainUnloadedException

The operation is attempted on an unloaded application domain.

Use this method overload to specify attributes that do not work correctly unless they are applied when a dynamic assembly is created. For example, security attributes such as SecurityTransparentAttribute and SecurityCriticalAttribute do not work correctly if they are added after a dynamic assembly has been created.

This method should be used only to define a dynamic assembly in the current application domain. For more information about this restriction, see the Load(AssemblyName) method overload.

This method overload is introduced in the .NET Framework 3.5.

The following code sample shows how to create a dynamic assembly that has the SecurityTransparentAttribute. The attribute must be specified as an element of an array of CustomAttributeBuilder objects.

The first step in creating the CustomAttributeBuilder is to obtain a constructor for the attribute. The constructor has no parameters, so the GetConstructor method is called with an empty array of Type objects to represent the types of the parameters. The second step is to pass the resulting ConstructorInfo object to the constructor for the CustomAttributeBuilder class, together with an empty array of type Object to represent the arguments.

The resulting CustomAttributeBuilder is then passed to the DefineDynamicAssembly method as the only element of an array.

The example code defines a module and a type in the new dynamic assembly, and then displays the assembly's attributes.

Imports System
Imports System.Reflection
Imports System.Reflection.Emit
Imports System.Security

Module Example

    Sub Main()

        ' Create a CustomAttributeBuilder for the assembly attribute.  
        '  
        ' SecurityTransparentAttribute has a parameterless constructor,  
        ' which is retrieved by passing an array of empty types for the 
        ' constructor's parameter types. The CustomAttributeBuilder is  
        ' then created by passing the ConstructorInfo and an empty array 
        ' of objects to represent the parameters. 
        
        Dim transparentCtor As ConstructorInfo = _
            GetType(SecurityTransparentAttribute).GetConstructor( _
                Type.EmptyTypes)
        Dim transparent As New CustomAttributeBuilder( _
            transparentCtor, _
            New Object() {} )

        ' Create a dynamic assembly Imports the attribute. The attribute is 
        ' passed as an array with one element. 
        Dim aName As New AssemblyName("EmittedAssembly")
        Dim ab As AssemblyBuilder = _
            AppDomain.CurrentDomain.DefineDynamicAssembly( _
                aName, _
                AssemblyBuilderAccess.Run, _
                New CustomAttributeBuilder() { transparent } )

        Dim mb As ModuleBuilder = ab.DefineDynamicModule( aName.Name )
        Dim tb As TypeBuilder = mb.DefineType( _
            "MyDynamicType", _
            TypeAttributes.Public )
        tb.CreateType()

        Console.WriteLine("{0}" & vbLf & "Assembly attributes:", ab)
        For Each attr As Attribute In ab.GetCustomAttributes(True)
            Console.WriteLine(vbTab & "{0}", attr)
        Next 
    End Sub 
End Module 

' This code example produces the following output: 

'EmittedAssembly, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null 
'Assembly attributes: 
'        System.Security.SecurityTransparentAttribute

.NET Framework

Supported in: 4.5, 4, 3.5 SP1, 3.0 SP1, 2.0 SP1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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

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