> 
> **Possible Duplicate:**  
> 
> [What is System.Void?](https://stackoverflow.com/questions/5450748/what-is-system-void)  
> 
> [Why not System.Void?](https://stackoverflow.com/questions/6408847/why-not-system-void) 
> 
> 
> 

I noticed that it is not allowed to use `typeof(System.Void)`. But `typeof(void)` is allowed.
When you use `typeof(System.String)` or `typeof(string)` there is no difference.

Why is this the case?