How to load Assembly at runtime and create class instance?
I have a assembly. In this assembly I have a class and interface. I need to load this assembly at runtime and want to create an object of the class and also want to use the interface.
Assembly MyDALL = Assembly.Load("DALL"); // DALL is name of my dll
Type MyLoadClass = MyDALL.GetType("DALL.LoadClass"); // LoadClass is my class
object obj = Activator.CreateInstance(MyLoadClass);
This is my code. How could it be improved?
If your assembly is in GAC or bin use the assembly name at the end of type name instead of Assembly.Load()
.
object obj = Activator.CreateInstance(Type.GetType("DALL.LoadClass, DALL", true));
You should Use Dynamic Method with for Improving. its faster than reflection..
Here is a sample code for creating Object using Dynamic Method..
public class ObjectCreateMethod
{
delegate object MethodInvoker();
MethodInvoker methodHandler = null;
public ObjectCreateMethod(Type type)
{
CreateMethod(type.GetConstructor(Type.EmptyTypes));
}
public ObjectCreateMethod(ConstructorInfo target)
{
CreateMethod(target);
}
void CreateMethod(ConstructorInfo target)
{
DynamicMethod dynamic = new DynamicMethod(string.Empty,
typeof(object),
new Type[0],
target.DeclaringType);
ILGenerator il = dynamic.GetILGenerator();
il.DeclareLocal(target.DeclaringType);
il.Emit(OpCodes.Newobj, target);
il.Emit(OpCodes.Stloc_0);
il.Emit(OpCodes.Ldloc_0);
il.Emit(OpCodes.Ret);
methodHandler = (MethodInvoker)dynamic.CreateDelegate(typeof(MethodInvoker));
}
public object CreateInstance()
{
return methodHandler();
}
}
//Use Above class for Object Creation.
ObjectCreateMethod inv = new ObjectCreateMethod(type); //Specify Type
Object obj= inv.CreateInstance();
This method takes only 1/10th time needed by Activator.
Check out http://www.ozcandegirmenci.com/post/2008/02/Create-object-instances-Faster-than-Reflection.aspx
Check out http://www.youtube.com/watch?v=x-KK7bmo1AM To modify his code to load multiple assemblies use
static Assembly CurrentDomain_AssemblyResolve(object sender, ResolveEventArgs args)
{
string assemblyName = args.Name.Split(',').First();
using (var stream = Assembly.GetExecutingAssembly().GetManifestResourceStream("YourNamespace." + assemblyName + ".dll"))
{
byte[] assemblyData = new byte[stream.Length];
stream.Read(assemblyData, 0, assemblyData.Length);
return Assembly.Load(assemblyData);
}
}
In your main method put
AppDomain.CurrentDomain.AssemblyResolve += CurrentDomain_AssemblyResolve;
Be sure to add your assemblies to your project and change the build action property to "Embedded Resource".