int[,] arr = new int[15, 20];
        private void button1_Click(object sender, EventArgs e)
        {
            Random randomGenerator = new Random();
            for (int i = 0; i<15; i++)
            {
                for (int j = 0; j<20; j++)
                {
                    int TextNum = randomGenerator.Next((int)numericUpDown1.Value, (int)numericUpDown2.Value);
                    arr[i, j] = TextNum;
                    TextBox textBox = new TextBox()
                    {
                        Text = TextNum.ToString(),
                        Location = new Point(40 + 105 * i, 40 + 30 * j),
                        Width = 100,
                        Height = 25,
                    };

                    Controls.Add(textBox);
                }
            }
            
            for (int i=0; i<15; i++)
            {
                for (int j = 0; j < 20; j++)
                {
                    Console.WriteLine(arr[i, j]);
                }
            }
        }

int[,] arr = new int[15, 20];
        private void button1_Click(object sender, EventArgs e)
        {
            Random randomGenerator = new Random();
            for (int i = 0; i<15; i++)
            {
                for (int j = 0; j<20; j++)
                {
                    int TextNum = randomGenerator.Next((int)numericUpDown1.Value, (int)numericUpDown2.Value);
                    arr[i, j] = TextNum;
                    TextBox textBox = new TextBox()
                    {
                        Text = TextNum.ToString(),
                        Location = new Point(40 + 105 * i, 40 + 30 * j),
                        Width = 100,
                        Height = 25,
                    };

                    Controls.Add(textBox);
                }
            }
            
            for (int i=0; i<15; i++)
            {
                for (int j = 0; j < 20; j++)
                {
                    Console.WriteLine(arr[i, j]);
                }
            }
        }