How to move object through the view direction of the mainCamera

Questions & Answers
1

First, I must say that I’ve searched in the forum and google, but it seems that noone have met this problem, and sorry everyone for my bad English

In the forum, everyone said that " just use Camera.main.transform.forward, which indicates the forward direction of the camera as a vector".

So i wrote

			if (Input.GetKey(KeyCode.UpArrow))
	{
		this.transform.position = Camera.mainCamera.transform.position - Camera.main.transform.forward;
	}
			if (Input.GetKey(KeyCode.DownArrow))
	{
		this.transform.position = Camera.mainCamera.transform.position + Camera.main.transform.forward;
	}
2

Try this:

#pragma strict

var speed = 4.0;  // Units per second

function Update () {
    if (Input.GetKey(KeyCode.UpArrow))
        {
           transform.position -= Camera.main.transform.forward * speed * Time.deltaTime;
        }
             if (Input.GetKey(KeyCode.DownArrow))
        {
           transform.position += Camera.main.transform.forward * speed * Time.deltaTime;
        }
    }