Break loop when colliding with object

I have a problem with breaking the loop, when it hits "Wall" or "Box" object, but I am not sure, how I should check it. I know the Collision method and to destroy objects with it, but I need to use it in this switch statement.

Code (CSharp):

1. void ExpolsionController(Vector3 position)
2.     {
3.         float x = position.x;
4.         float y = position.y;
5.         float z = position.z;
6.         for (int i = 0; i < 4; i++)
7.         {
8.         outer:
9.             for (int j = 0; j < bombExpoltionArea; j++)
10.             {
11.  
12.                 switch (i)
13.                 {
14.                     case (0):
15.                         Instantiate(explosion, new Vector3(x + j, y, z), Quaternion.identity);
16.                         if (Collision.Equals("Wall", "Box"))
17.                             goto outer;
18.                         break;
19.                     case (1):
20.                         Instantiate(explosion, new Vector3(x - j, y, z), Quaternion.identity);
21.                         break;
22.                     case (2):
23.                         Instantiate(explosion, new Vector3(x, y, z + j), Quaternion.identity);
24.                         break;
25.                     case (3):
26.                         Instantiate(explosion, new Vector3(x, y, z - j), Quaternion.identity);
27.                         break;
28.                 }
29.             }
30.      

 

make a bool in OnCollisionEnter()?