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TypeBuilder Class

Defines and creates new instances of classes during run time.

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

public final class TypeBuilder extends Type implements _TypeBuilder


The HostProtectionAttribute attribute applied to this type or member has the following Resources property value: MayLeakOnAbort. The HostProtectionAttribute does not affect desktop applications (which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser). For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes.

TypeBuilder is the root class used to control the creation of dynamic classes in the runtime. TypeBuilder provides a set of routines that are used to define classes, add methods and fields, and create the class inside the runtime. A new TypeBuilder can be created from a dynamic module.

To create an array type, pointer type, or byref type for an incomplete type that is represented by a TypeBuilder object, use the MakeArrayType method, MakePointerType method, or MakeByRefType method, respectively.

This section contains two code examples. The first example shows how to create a dynamic type with a field, constructor, property, and method. The second example builds a method dynamically from user input.

Example one

The following code example shows how to define a dynamic assembly with one module. The module in the example assembly contains one type, MyDynamicType, which has a private field, a property that gets and sets the private field, constructors that initialize the private field, and a method that multiplies a user-supplied number by the private field value and returns the result.

The AssemblyBuilderAccess.RunAndSave field is specified when the assembly is created. The assembly code is used immediately, and the assembly is also saved to disk so that it can be examined with MSIL Disassembler (Ildasm.exe) or used in another program.

No code example is currently available or this language may not be supported.

Example two

The following code sample demonstrates how to build a dynamic type by using TypeBuilder.

No code example is currently available or this language may not be supported.


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 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

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

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0