Trouble Sharing Variables between files in c#

Question

I'm having trouble finding out how to share variables between different c# files. I'm relatively new to coding in this language and i don't know how to access a Boolean from one file in another.

I can provide code if needed, i'm using unity if that matters. I'm being told that the variable doesn't exist in current context. ask if more info is needed i don't really know what you nee to answer this.

this is the first file

using System.Collections;
using System.Collections.Generic;
using UnityEngine;



public class floorAndWallCheck : MonoBehaviour {
    public bool isGrounded = false;

    public void OnTriggerEnter2D(Collider2D floor){
        if (floor.tag == "floor") {
            isGrounded = true;
        }else {
            isGrounded = false;
        }
    }
}

this is some lines from second file

void Update () {
    //left
    if (Input.GetKey("a")) {
        player1.transform.Translate(Vector3.left * Time.deltaTime * speed);
    }
    //right
    if (Input.GetKey("d")) {
        player1.transform.Translate(Vector3.right * Time.deltaTime * speed);
    }
    //up
    if (Input.GetKey("w") && isGrounded == true) {
        player1.transform.Translate(Vector3.up * Time.deltaTime * jumpForce);                       
    }

Answer 1

Since it seems that you might want to check isGrounded for multiple players I would not use static as mentioned in the other answer since then it is static for every instance of floorAndWallCheck .

---

Instead you have to access the member of the according instance.

Assuming the floorAndWallCheck component is eg attached to the player1 object you can do

private floorAndWallCheck player1FloorCheck;

private void Awake ()
{
   player1FloorCheck = player1.GetComponent<floorAndWallCheck>(); 
}

private void Update()
{

    //...

    Input.GetKey("w") && player1FloorCheck.isGrounded)
    {
        // ...
    }
}

---

or instead of using GetComponent you can make it either public

public floorAndWallCheck player1FloorCheck;

or use [SerializeField]

[SerializeField] private floorAndWallCheck player1FloorCheck;

and reference the according component in the Inspector (via drag & drop)

---

Find more ways for accessing other classe's members here

Answer 2

Here it looks like you want to use static

public class floorAndWallCheck : MonoBehaviour {
    static public bool isGrounded = false;

    public void OnTriggerEnter2D(Collider2D floor){
/// etc

Then in the other file

if (Input.GetKey("w") && floorAndWallCheck.isGrounded == true) {

https://unity3d.com/learn/tutorials/topics/scripting/statics

The problem is that this will make the variable global to all instances of a floorAndWallCheck

I don't think you want that even if you are asking for it in your question. Probably what you really want to do is not "share the variable" but instead have a variable of that type be a parameter to whatever function you were using in the 2nd file. In this way you can "pass" the data from one place to another.