CompileConstructor

static Delegate CompileConstructor<TNew>(params Type[] types)
{
  ConstructorInfo ctor = typeof(TNew).GetConstructor(types);
  var parameters = ctor.GetParameters().Select(
    x => Expression.Parameter(x.ParameterType, x.Name));
  var newx = Expression.New(ctor, parameters);
  return Expression.Lambda(newx, parameters).Compile();
}