Reflection Emit to create class instance

Question

I want to use Reflection Emit to create an instance of a class with arbitrary constructor parameters. This is how my code looks like: ``` public delegate object ObjectActivator(params object[] args); static void Main(string[] args) { var ao = new { ID = 10000, FName = "Sample", SName = "Name" }; var t = ao.GetType(); var info = t.GetConstructor(new Type[] { typeof(int), typeof(string), typeof(string) }); var objActivatorEmit = GetActivatorEmit(info); var obj = createdActivatorEmit(4, "Foo", "Bar"); } public static ObjectActivator GetActivatorEmit(ConstructorInfo ctor) { ParameterInfo[] paramsInfo = ctor.GetParameters(); DynamicMethod method = new DynamicMethod("CreateInstance", typeof(object), new Type[] { typeof(object[]) }); ILGenerator gen = method.GetILGenerator(); for (int i = 0; i < paramsInfo.Length; i++) { Type t = paramsInfo[i].ParameterType; gen.Emit(OpCodes.Ldarg_0); // Push array (method argument) gen.Emit(OpCodes.Ldc_I4, i); // Push i gen.Emit(OpCodes.Ldelem_Ref); // Pop…

Accepted Answer

The error message indicates that the anonymous type's constructor isn't public. I think anonymous type constructors are always `internal`, so you'll need to skip visibility checks by using a different `DynamicMethod` constructor:

```
DynamicMethod method = new DynamicMethod("CreateInstance", typeof(object), new Type[] { typeof(object[]) }, true);
```

Note that this not work in partial trust scenarios.

Reflection Emit to create class instance

Solution

Problem