Friday, August 24, 2012


How to: Load Assemblies into an Application Domain

There are several ways to load an assembly into an application domain. The recommended way is to
use the static (Shared in Visual Basic) Load method of the System.Reflection.Assembly class. Other
ways assemblies can be loaded include:
The LoadFrom method of the Assembly class loads an assembly given its file location. Loading
assemblies with this method uses a different load context.
The ReflectionOnlyLoad and ReflectionOnlyLoadFrom methods load an assembly into the
reflection-only context. Assemblies loaded into this context can be examined but not executed,
allowing the examination of assemblies that target other platforms. See How to: Load
Assemblies into the Reflection-Only Context.
Note
The reflection-only context is new in the .NET Framework version 2.0.
Methods such as CreateInstance and CreateInstanceAndUnwrap of the AppDomain class can
load assemblies into an application domain.
The GetType method of the Type class can load assemblies.
The Load method of the System.AppDomain class can load assemblies, but is primarily used for
COM interoperability. It should not be used to load assemblies into an application domain other
than the application domain from which it is called.
Note
Starting with the .NET Framework version 2.0, the runtime will not load an assembly that was
compiled with a version of the .NET Framework that has a higher version number than the currently
loaded runtime. This applies to the combination of the major and minor components of the version
number.
You can specify the way the just-in-time (JIT) compiled code from loaded assemblies is shared
between application domains. For more information, see Application Domains and Assemblies.
Example
The following code loads an assembly named "example.exe" or "example.dll" into the current
application domain, gets a type named Example from the assembly, gets a parameterless method
named MethodA for that type, and executes the method. For a complete discussion on obtaining
information from a loaded assembly, see Dynamically Loading and Using Types.
Visual Basic
Copy Code
Imports System
Imports System.Reflection
Public Class Asmload0
Public Shared Sub Main()
' Use the file name to load the assembly into the current
' application domain.
Dim a As [Assembly] = [Assembly].Load("example")
' Get the type to use.
Dim myType As Type = a.GetType("Example")
' Get the method to call.
Dim mymethod As MethodInfo = myType.GetMethod("MethodA")
' Create an instance
Dim obj As Object = Activator.CreateInstance(myType)
' Execute the method.
mymethod.Invoke(obj, Nothing)
End Sub
End Class
C#
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using System;
using System.Reflection;
public class Asmload0
{
public static void Main ()
{
// Use the file name to load the assembly into the current
// application domain.
Assembly a = Assembly.Load("example");
// Get the type to use.
Type myType = a.GetType("Example");
// Get the method to call.
MethodInfo mymethod = myType.GetMethod("MethodA");
// Create an instance.
Object obj = Activator.CreateInstance(myType);
// Execute the method.
mymethod.Invoke(obj,null);
}
}

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