Question

I am currently making a Minesweeper clone.
I made an algorithm that, when clicked on a tile with 0 surrounding mines, reveals all neighbors with 0 surrounding mines then all neighbors of them with 0 surrounding mines… (recursion).
This result only needs one click:

It works like it should but it is too slow. The original Minesweeper reveals these tiles instantly, but in my case, they have a little delay between the reveals.

I wrote this code:

private void RevealNeighbor(int x, int y) {
    foreach(var neighbor in _neighbors) {
        try {
            Tile tile = _tiles[x + neighbor[0], y + neighbor[1]];
            if(tile.TileType == TileType.Empty && tile.Hidden) {
                tile.Reveal();
                if(tile.Number == 0) {
                    RevealNeighbor(x + neighbor[0], y + neighbor[1]);
                }
            }
        }
        catch(IndexOutOfRangeException) {
        }
    }
}

_neighbors is an array of arrays, that has the 8 position offsets for the neighbors:

private readonly int[][] _neighbors = new[] {
                                          new[] {-1, -1},
                                          new[] {0, -1},
                                          new[] {1, -1},
                                          new[] {1, 0},
                                          new[] {1, 1},
                                          new[] {0, 1},
                                          new[] {-1, 1},
                                          new[] {-1, 0}
                                      };

How can I make it faster?

Answer 1

Use the SuspendLayout method, to draw only when needed:

*false is a default for the designer, find out what it means

this.SuspendLayout();
... logic      
this.ResumeLayout(false);

ALSO – avoid abusing the Exceptions mechanism, it is not efficient and bad practice

instead use a wall (extra tile on the end of the matrix indicating.. well.. a wall).