I tried to replicate Minesweeper as a small practise in coding with Windows Forms.

After some time, when I ran the program, the Form did neither display nor show up in the task bar.

Eventually, I was able to track down the problem to a function I wrote, that was called in the Form1 constructor. Whenever it was in its constructor, the Form did not show up whenever I pressed F5. There are no error messages shown, it's just the window not popping up.

Here is the code I wrote. The function causing problems is the Setup() function called in the Form1 constructor:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Minesweeper
{
    public partial class Form1 : Form
    {
        private int bombs = 40;
        private Size gridSize = new Size (20, 20);

        private Random random = new Random();

        private int[,] values;

        public Form1()
        {
            InitializeComponent();
            Setup();
        }

        //Setup / Game start
        private void Setup()
        {
            //Set grid size
            values = new int[gridSize.Width, gridSize.Height];

            //Place bombs
            if (bombs < gridSize.Width * gridSize.Height)
            {
                for (int i = 0; i < bombs; i  )
                {
                    Point p = new Point(random.Next(0, gridSize.Width), random.Next(0, gridSize.Height));

                    while (values[p.X, p.Y] != 9)
                    {
                        p = new Point(random.Next(0, gridSize.Width), random.Next(0, gridSize.Height));
                    }

                    values[p.X, p.Y] = 9;
                }
            }

            //Calculate values
            for (int x = 0; x < gridSize.Width; x  )
            {
                for (int y = 0; y < gridSize.Height; y  )
                {
                    if (values[x, y] >= 9)
                    {
                        ChangeValueAt(x - 1, y - 1, 1);
                        ChangeValueAt(x - 1, y, 1);
                        ChangeValueAt(x - 1, y   1, 1);
                        ChangeValueAt(x, y - 1, 1);
                        ChangeValueAt(x, y   1, 1);
                        ChangeValueAt(x   1, y - 1, 1);
                        ChangeValueAt(x   1, y, 1);
                        ChangeValueAt(x   1, y   1, 1);
                    }
                }
            }
        }

        //Change value in grid
        private void ChangeValueAt(int x, int y, int changeBy)
        {
            if (values.GetLength(0) > x && values.GetLength(1) > y && values[x, y] != 9)
            {
                values[x, y]  = changeBy;
            }
        }
    }
}

Does anyone know why that happens?

PS: I am very new to coding, I know my code is often not very tidy and there might be a few bad memory usages, but I would just like to know if anyone could help me out here.

CodePudding user response：

That's because the while-loop never ends. The fist time the for-loop runs, no value[,x,y] has been set to 9 yet. So, the while condition values[p.X, p.Y] != 9 will always be true.

I would write

for (int i = 0; i < bombs; i  ) {
    Point p;
    do {
        p = new Point(random.Next(0, gridSize.Width),
                      random.Next(0, gridSize.Height));
    } while (values[p.X, p.Y] == 9);

    values[p.X, p.Y] = 9;
}

Also, the lower bounds must be tested as well:

private void ChangeValueAt(int x, int y, int changeBy)
{
    if (0 <= x && x < values.GetLength(0) &&
        0 <= y && y < values.GetLength(1) &&
        values[x, y] != 9) {

        values[x, y]  = changeBy;
    }
}