How to declare an array of objects C#

Question

I'm making a 2D tile map for a game. I Have a Cell class (tiles) makes cell objects that have 4 attributes: TopWall, BottomWall, LeftWall, RightWall. The wall may or may not be there, so those attributes are boolean true or false, and if they are true, a line will be drawn down that cell wall (not allowing the player to pass through the cell). I want to declare a (2 dimensional? As in, row, and column) array of my cell objects called Map1 (as they will make up a game map). Then i want to set each member of the array to having specific wall attributes. Here is what i have:

Cell.cs

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 Map
{
    public class Cell : PictureBox
    {
        bool LeftWall; 
        bool TopWall; 
        bool RightWall;
        bool BottomWall;

        public Cell(bool TopWall, bool RightWall, bool BottomWall, bool LeftWall)
        {
            this.TopWall = TopWall;
            this.RightWall = RightWall;
            this.BottomWall = BottomWall;
            this.LeftWall = LeftWall;
        }
    }
}

This is me starting to attempt making the array of cell objects and set the wall attributes: Form1.cs

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 Map
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        /// <summary>
        /// Array of tiles
        /// </summary>
        //PictureBox[,] Boxes = new PictureBox[4,4];
        public void initiateArray()
        {
            Cell[,] Map1 = new Cell[4, 4];

            for (int row = 0; row < 4; row++)
            {
                for (int column = 0; column < 4; column++)
                {
                    Map1[row, column] = new Cell();
                }
            }

            Map1[0, 0] = new Cell(true, false, false, true);
            Map1[0, 1] = new Cell(false, false, false, true);
        }


      /*int [][] Walls = new int[][] {
      new int[] {0,0}, new int[] {1,0,0,1},
      new int[] {1,0}, new int[] {1,0,1,0},
      new int[] {0,1}, new int[] {0,0,0,1}, 
      new int[] {1,1}, new int[] {1,1,1,0}, 
      new int[] {2,0}, new int[] {1,1,0,0},
      new int[] {2,1}, new int[] {0,0,0,1}, 
      new int[] {3,1}, new int[] {1,0,1,0}, 
      new int[] {0,2}, new int[] {0,0,1,1}, 
      new int[] {1,2}, new int[] {1,0,1,0}, 
      new int[] {2,2}, new int[] {0,1,1,0}};*/



        #region Runtime load
        /// <summary>
        /// Build the map when window is loaded
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void Form1_Load(object sender, EventArgs e)
        {
            BuildMap();
        }
        #endregion

        #region Build grid
        /// <summary>
        /// Draw every tile on the map
        /// </summary>
        public void BuildMap()
        {
            for (int row = 0; row < 3; row++)
            {
                for (int column = 0; column < 3; column++)
                {
                    DrawCell(row, column);
                }
            }
            //draw the exit box
            DrawCell(1, 3);
        }
        #endregion

        #region Draw
        /// <summary>
        /// Draw one tile
        /// </summary>
        /// <param name="row"></param>
        /// <param name="column"></param>
        public void DrawCell(int row, int column)
        {
            Map1[row, column] = new Cell();
            Map1[row, column].Height = 100;
            Map1[row, column].Width = 100;
            Map1[row, column].BorderStyle = BorderStyle.FixedSingle;
            Map1[row, column].BackColor = Color.BurlyWood;
            Map1[row, column].Location = new Point((Map[row, column].Width * column), (Map[row, column].Height * row));
            this.Controls.Add(Map1[row, column]);

           // System.Drawing.Pen myPen;
           // myPen = new System.Drawing.Pen(System.Drawing.Color.Red);
            //System.Drawing.Graphics formGraphics = this.CreateGraphics();


            //formGraphics.DrawLine(myPen, 0, 0, 200, 200);
            //myPen.Dispose();
            //formGraphics.Dispose();
        }



        public void DrawWalls(int row, int column)
        {

        }
        #endregion
    }


}

It is showing a lot of errors and i was wondering if anyone can see where i'm going wrong. Thanks.

Answer 1

Common mistake. Cell[][] is not the same as Cell[,].

Also

var foo = new Cell[4,4];
Console.WriteLine(foo.Length);

Gives 16 and NOT 4, as your code assumed.

This is how you should do it, if you want to use the array's "Length" information.

    public void initiateArray()
    {
        Cell[,] Map1 = new Cell[4, 4];

        for (int row = 0; row < Map1.GetLength(0); row++)
        {
            for (int column = 0; column < Map1.GetLength(1); column++)
            {
                Map1[row, column] = new Cell();
            }
        }

        Map1[0, 0] = new Cell(true, false, false, true);
        Map1[0, 1] = new Cell(false, false, false, true);
    }

or (since I have absolutely no faith in my own ability in Off By One bugs, using Linq)

    public void initiateArray()
    {
        Cell[,] Map1 = new Cell[4, 4];

        foreach(var row in Enumerable.Range(0, Map1.GetLength(0)))
        foreach(var column in Enumerable.Range(0, Map1.GetLength(1)))
        {
                Map1[row, column] = new Cell();         
        }
        Map1[0, 0] = new Cell(true, false, false, true);
        Map1[0, 1] = new Cell(false, false, false, true);
    }

Answer 2

First make sure PictureBox has a non-parameterized constructor implemented.

Second and thrid Map1[i] = new Cell(); You initialized a matrix, you need two nested loops to traverse the whole thing and you need to access it by using the comma notation [row, col]. you use row not i in your loop.

Fourth you are missing a 'new' at the end Map1[0,0] = Cell(true, false, false, true);