Error: "Use of unassigned local variable 'BoxPrefab'". How do I fix this?-CodePudding

I'm working on my game, it's my first project on Unity. In short, it has 3d Grid and should have box in each grid cell. I need to instantiate Box prefab in each cell, but I'm getting this error: "Assets\BoxGrid.cs(26,67): error CS0165: Use of unassigned local variable 'BoxPrefab'". How do I assign GameObject BoxPrefab a Prefab using only script?

public class BoxGrid
{
    private GameObject BoxPrefab = GameObject.Find("Box");

    private int width;
    private int height;
    private int length;
    private float CellSize;
    private int[,,] BoxGridArray;

    public BoxGrid(int width, int height, int length, float CellSize) {
        this.width = width;
        this.height = height;
        this.length = length;
        this.CellSize = CellSize;

        BoxGridArray = new int[width, height, length];

        for (int x = 0; x < BoxGridArray.GetLength(0); x  ) {
            for (int y = 0; y < BoxGridArray.GetLength(1); y  ) {
                for (int z = 0; z < BoxGridArray.GetLength(2); z  ) {
                    GameObject BoxPrefab = GameObject.Instantiate(BoxPrefab, GetPosition(x, y, z)   new Vector3(CellSize, CellSize, CellSize) * .5f, Quaternion.identity) as GameObject;
                    
                    Debug.DrawLine(GetPosition(x, y, z), GetPosition(x, y, z   1), Color.white, 100f);
                    Debug.DrawLine(GetPosition(x, y, z), GetPosition(x, y   1, z), Color.white, 100f);
                    Debug.DrawLine(GetPosition(x, y, z), GetPosition(x   1, y, z), Color.white, 100f);
                }
            }
        }
    }
    private Vector3 GetPosition(int x, int y, int z) {
        return new Vector3(x, y, z) * CellSize;
    }
}

Code below is other script with MonoBehaviour that defines Grid's parameters.

public class GridCreate : MonoBehaviour
{
    public void Start() {
        BoxGrid Grid = new BoxGrid(4, 4, 4, 25f);
    }
}

How do I fix this error?

I'm trying to make Minesweeper game in 3d even though I'm newbie in programming. I tried to assign GameObject a Prefab like this "private GameObject BoxPrefab = GameObject.Find("Box"); " but it doesn't seem to work, is there any other way?

CodePudding user response：

By writing

GameObject BoxPrefab = GameObject.Instantiate(BoxPrefab, GetPosition(x, y, z)   new Vector3(CellSize, CellSize, CellSize) * .5f, Quaternion.identity) as GameObject;

you "hide" your class field and basically overrule it with this local variable with the same name.

That local variable isn't initialized until Instantiate returns something => you can't have the same variable as parameter.

you probably just want to use

Object.Instantiate(BoxPrefab, GetPosition(x, y, z)   new Vector3(CellSize, CellSize, CellSize) * .5f, Quaternion.identity) as GameObject;

as I don't see where you ever use the local variable later anyway.

I would also avoid issues with static context etc. rather explicitly move this into the constructor

public BoxGrid(int width, int height, int length, float CellSize) 
{       
    GameObject BoxPrefab = GameObject.Find("Box");

...