Creating objects without Activator.CreateInstance

Tue, 24 May 2016

I am not going to explain why I had to do this.

public static class LambdaActivator
{
    public static Func<TResult> Generate<TResult>()
    {
        var constructorInfo = typeof(TResult).GetConstructor(new Type[] { });

        Expression<Func<TResult>> expression = Expression.Lambda<Func<TResult>>(Expression.New(constructorInfo));
        Func<TResult> functor = expression.Compile();
        return functor;
    }


    public static Func<object> Generate(Type outputType)
    {
        var constructorInfo = outputType.GetConstructor(new Type[] { });

        Expression<Func<object>> expression = Expression.Lambda<Func<object>>(Expression.New(constructorInfo));
        Func<object> functor = expression.Compile();
        return functor;
    }
}


var result = LambdaActivator.Generate<Something>().Invoke();
var result = LambdaActivator.Generate(typeof(Something)).Invoke() as Something;