Creating a 2D Array in C#

private void btnMC(
  object sender, System.EventArgs e) {
   const int r = 10;
   const int c = 4;
   
   int [,] array = new int [r, c];
   
   for (int i = 0; i < r; i++) {
      for (int j = 0; j < c; j++) {
         array[i,j] = i*j;
      }
   }
   for (int i = 0; i < r; i++) {
      for (int j = 0; j < c; j++) {
         string theItem = "array ["
           + i.ToString() + "," + j.ToString() +
           "] is " + array[i,j].ToString() + ".";
         lstMC.Items.Add(theItem);
      }
   }
}