why GetComponent returns null reference for imageEffect?

问题

this problem is unsolvable or what?i don't need to provide any code example it just doesn't work to anyone!and i don't know how its possible,you just have to try this : GetComponent<DepthOfField>().enabled = false;

assume that we have a MainCamera object and we attach it a DepthOfField image effect Script.and we create another script named whatever and attach it to the MainCamera and in the whatever script we just call this:

void Start() {
  GetComponent<DepthOfField>().enabled = false;
}

shouldn't it work?well it doesn't, it returns null reference exception even if the script is attached to the main camera.is it fixable? and if yes i need it !

回答1:

It should work because they are both attached to the same GameObject. Although, there are many other ways you can try to fix this.

You can just do

 DepthOfField myDept;

void Start() {
myDept = GameObject.Find("MainCamera").GetComponent<DepthOfField>();
myDept.enabled = false;
}

Or You could make DepthOfField public then assign the DepthOfField from the Editor. For example,

public DepthOfField myDept; 

//Drag and Drop the MainCamera GameObject from the scene to this and it will automatically assign the DepthOfField script to the myDept.

Then you can do

myDept.enabled = false;

For this to work, DepthOfField must be attached to the MainCamera GameObject.

来源：https://stackoverflow.com/questions/30003776/why-getcomponent-returns-null-reference-for-imageeffect