Change Direction of Particles by Player Input?

In my game the player has a particle system attached to it as a child so it'll follow the player around the game. I'd like to change the direction the particles emit from player input. For instance, if I move up the particles are emitting downward. If I move left the particles will emit to the right. Is there a possible way to do this? Here is my code of how I want the code set up if all possible. If there is way to do this in C# and not Javascript I could work with that as well.

Code (JavaScript):

1. function Update() {
2. if(Input.GetKey(KeyCode.UpArrow)){
3. //change direction of particles
4. }
5. if(Input.GetKey(KeyCode.DownArrow)){
6. //change direction of particles
7. }
8. if(Input.GetKey(KeyCode.LeftArrow)){
9. //change direction of particles
10. }
11.  
12. if(Input.GetKey(KeyCode.RightArrow)){
13. //change direction of particles
14. }
15.  
16. }

 

You could just rotate the emitter, or if you have a set number of directions e.g. 8, you could create separate emitters for each direction then switch them on and off.