Unity3d bug with switching cameras?

Question

C++ / C#

public Camera camera1;
    public Camera camera2;
    // Use this for initialization
    void Start () {
     
        camera1 = (Camera)(object)GameObject.FindGameObjectWithTag("MainCamera");
        camera2 = GetComponent<Camera>();
        camera1.enabled = true;
        camera2.enabled = false;

void Update () {
        if (Input.GetKey(KeyCode.W))
        {
           camera2.enabled = !camera2.enabled;
            camera1.enabled = !camera1.enabled;
            transform.Translate(Vector3.forward * Time.deltaTime * speed);
        };

Unity gives the following error when starting:

InvalidCastException: Cannot cast from source type to destination type.
CubeScript.Start() (at Assets/scripts/CubeScript.cs:12)

-That is, it swears at the line

camera1 = (Camera)(object)GameObject.FindGameObjectWithTag("MainCamera");

- due to type ghosts, but I can’t convert from GameObject to Camera in a different way - because I need to assign one specific camera from two cameras on the stage to this field, and this, as I understand it, is the only way to get a link to an external an object?
And then when you press the corresponding W key
, an error occurs:

nassignedReferenceException: The variable camera2 of CubeScript has not been assigned.
You probably need to assign the camera2 variable of the CubeScript script in the inspector.
CubeScript.Update() (at Assets/scripts/CubeScript.cs:23)

-why does unity say that the value for the camera2 variable is not assigned? After all, here - camera2 = GetComponent<Camera>();
I assign a value to it - the object receives the camera that I "hung" on the object, and

camera1 = (Camera)(object)GameObject.FindGameObjectWithTag("MainCamera");

- the studio gets the "main camera" - i.e. I have two cameras in the scene

Answer 1

You misunderstand the essence of classes and components, carefully read the documentation. GameObject is not a component, you cannot magically get a component from it by casting to another class, for this there is a special method GameObject.GetComponent . Also, in your case, the FindGameObjectWithTag construct can be replaced with a call to Camera.main , the result will be the same. This is not good practice in the context of cameras, but that's up to you. As for the second error, it happens due to the fact that in your start in the first line an exception is thrown, which breaks the method flow, and all subsequent lines are not called, so camera2 remains null.

Answer 2

camera1 = Camera.main
Regarding the second camera
Most likely, there is no such component on the millet object. Just in case, add the attribute RequireComponentr(typeof(Camera)) before the script class. Then remove the script from the object and hang again.
Or assign a camera in the inspector manually