DynamicMethod Constructor (String, Type, Type[], Boolean)


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Initializes an anonymously hosted dynamic method, specifying the method name, return type, parameter types, and whether just-in-time (JIT) visibility checks should be skipped for types and members accessed by the Microsoft intermediate language (MSIL) of the dynamic method.

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

public DynamicMethod(
	string name,
	Type returnType,
	Type[] parameterTypes,
	bool restrictedSkipVisibility


Type: System.String

The name of the dynamic method. This can be a zero-length string, but it cannot be null.

Type: System.Type

A Type object that specifies the return type of the dynamic method, or null if the method has no return type.

Type: System.Type[]

An array of Type objects specifying the types of the parameters of the dynamic method, or null if the method has no parameters.

Type: System.Boolean

true to skip JIT visibility checks on types and members accessed by the MSIL of the dynamic method, with this restriction: the trust level of the assemblies that contain those types and members must be equal to or less than the trust level of the call stack that emits the dynamic method; otherwise, false.

Exception Condition

An element of parameterTypes is null or Void.


name is null.


returnType is a type for which Type.IsByRef returns true.

The dynamic method that is created by this constructor is associated with an anonymous assembly instead of an existing type or module. The anonymous assembly exists only to provide a sandbox environment for dynamic methods, that is, to isolate them from other code. This environment makes it safe for the dynamic method to be emitted and executed by partially trusted code.

Anonymously hosted dynamic methods do not have automatic access to any types or members that are private, protected, or internal (Friend in Visual Basic). This is different from dynamic methods that are associated with an existing type or module, which have access to hidden members in their associated scope.

Specify true for restrictedSkipVisibility if your dynamic method has to access types or members that are private, protected, or internal. This gives the dynamic method restricted access to these members. That is, the members can be accessed only if the following conditions are met:

  • The target members belong to an assembly that has a level of trust equal to or lower than the call stack that emits the dynamic method.

  • The call stack that emits the dynamic method is granted ReflectionPermission with the ReflectionPermissionFlag.RestrictedMemberAccess flag. This is always true when the code is executed with full trust. For partially trusted code, it is true only if the host explicitly grants the permission.


    If the permission has not been granted, a security exception is thrown when CreateDelegate is called or when the dynamic method is invoked, not when this constructor is called. No special permissions are required to emit the dynamic method.

For example, a dynamic method that is created with restrictedSkipVisibility set to true can access a private member of any assembly on the call stack if the call stack has been granted restricted member access. If the dynamic method is created with partially trusted code on the call stack, it cannot access a private member of a type in a .NET Framework assembly, because such assemblies are fully trusted. 

If restrictedSkipVisibility is false, JIT visibility checks are enforced. The code in the dynamic method has access to public methods of public classes, and exceptions are thrown if it tries to access types or members that are private, protected, or internal.

When an anonymously hosted dynamic method is constructed, the call stack of the emitting assembly is included. When the method is invoked, the permissions of the emitting call stack are used instead of the permissions of the actual caller. Thus, the dynamic method cannot execute at a higher level of privilege than that of the assembly that emitted it, even if it is passed to and executed by an assembly that has a higher trust level.

This constructor specifies the method attributes MethodAttributes.Public and MethodAttributes.Static, and the calling convention CallingConventions.Standard.


This constructor was introduced in the .NET Framework 3.5 or later.

.NET Framework
Available since 2.0
Portable Class Library
Supported in: portable .NET platforms
Windows Phone Silverlight
Available since 7.1
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