Creating Code at runtime with C#

Reflection can be used to create code at runtime. It includes namespace called System.Reflection.Emit that houses set of builder classes that take care of creating code. The process is just like normal process. We create an assembly following by a module within the assembly, and finally types within the module.

Builder Classes


NameDescription for Used to Buid
AssemblyBuilder Assemblies at runtime
ConstructorBuilder Constructors at runtime
EnumBuilder Enumerations at runtime
EventBulder EventBulder
FieldBuilder Fields at runtime
LocalBuilder Local variables
MethodBuilder Methods at runtime
ModuleBuilder Modules at runtime
ParameterBuilder Method parameters at runtime
PropertyBuilder Properties at runtime
TypeBuilder Types at runtime

AssemblyName myTempName = new AssemblyName();
myTempName.Name = "MyTempAssembly";
AssemblyBuilder myAssemBldr = AppDomain.CurrentDomain.DefineDynamicAssembly(tempName, AssemblyBuilderAccess.RunAndSave);
ModuleBuilder modBldr = myAssemBldr.DefineDynamicModule("MainMod", "MyTempAssembly.dll");
TypeBuilder typeBldr = modBldr.DefineType("MyNewType", TypeAttributes.Public | TypeAttributes.Class);

TypeBuilder Definitions


DefineConstructor Constructors
DefineDefaultConstructor Parameterless constructor
DefineEvent Events
DefineField Fields
DefineGenericParameters Generic parameters
DefineMethod Methods
DefineMethodOverride Overloads for methods
DefineNestedType New types
DefinePInvokeMethod Calls to external code
DefineProperty Properties


Creating Code at runtime