AppDomain.Load Method (Byte[])

Loads the Assembly with a common object file format (COFF) based image containing an emitted Assembly.

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

public Assembly Load (
	byte[] rawAssembly
public final Assembly Load (
	byte[] rawAssembly
public final function Load (
	rawAssembly : byte[]
) : Assembly
Not applicable.



An array of type byte that is a COFF-based image containing an emitted assembly.

Return Value

The loaded assembly.

Exception typeCondition


rawAssembly is a null reference (Nothing in Visual Basic).


rawAssembly is not a valid assembly.


Version 2.0 or later of the common language runtime is currently loaded and rawAssembly was compiled with a later version.


The operation is attempted on an unloaded application domain.


An assembly or module was loaded twice with two different evidences.

For more information, see the Load(AssemblyName) method overload.

The following sample demonstrates the use of loading a raw assembly.

For this code example to run, you must provide the fully qualified assembly name. For information about how to obtain the fully qualified assembly name, see Assembly Names.

using System;
using System.IO;
using System.Reflection;
using System.Reflection.Emit;

class Test {
   public static void Main() {
      AppDomain currentDomain = AppDomain.CurrentDomain;
      InstantiateMyType(currentDomain);   // Failed!

      currentDomain.AssemblyResolve += new ResolveEventHandler(MyResolver);
      InstantiateMyType(currentDomain);   // OK!
   static void InstantiateMyType(AppDomain domain) {
      try {
	 // You must supply a valid fully qualified assembly name here.
         domain.CreateInstance("Assembly text name, Version, Culture, PublicKeyToken", "MyType");
      } catch (Exception e) {
   // Loads the content of a file to a byte array. 
   static byte[] loadFile(string filename) {
      FileStream fs = new FileStream(filename, FileMode.Open);
      byte[] buffer = new byte[(int) fs.Length];
      fs.Read(buffer, 0, buffer.Length);
      return buffer;

   static Assembly MyResolver(object sender, ResolveEventArgs args) {
      AppDomain domain = (AppDomain) sender;

      // Once the files are generated, this call is
      // actually no longer necessary.
      byte[] rawAssembly = loadFile("temp.dll");
      byte[] rawSymbolStore = loadFile("temp.pdb");
      Assembly assembly = domain.Load(rawAssembly, rawSymbolStore);

      return assembly;
   // Creates a dynamic assembly with symbol information
   // and saves them to temp.dll and temp.pdb
   static void EmitAssembly(AppDomain domain) {
      AssemblyName assemblyName = new AssemblyName();
      assemblyName.Name = "MyAssembly";

      AssemblyBuilder assemblyBuilder = domain.DefineDynamicAssembly(assemblyName, AssemblyBuilderAccess.Save);
      ModuleBuilder moduleBuilder = assemblyBuilder.DefineDynamicModule("MyModule", "temp.dll", true);
      TypeBuilder typeBuilder = moduleBuilder.DefineType("MyType", TypeAttributes.Public);

      ConstructorBuilder constructorBuilder = typeBuilder.DefineConstructor(MethodAttributes.Public, CallingConventions.Standard, null);
      ILGenerator ilGenerator = constructorBuilder.GetILGenerator();
      ilGenerator.EmitWriteLine("MyType instantiated!");


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

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0