const int n = 4;
Button[,] Num; 
Random Rand = new Random();
private void Randomize()
{
 
    int index = 16;
    while (index != 0)
    {
        int Rx = Rand.Next(n);
        int Ry = Rand.Next(n);
        if (index == 16) { Num[Rx, Ry].Text = index.ToString(); Num[Rx, Ry].Hide(); index--; }
        else
            if (Num[Rx, Ry].Text == "") { Num[Rx, Ry].Text = index.ToString(); --index; }
    }
 
 
}
 
private void button1_Click(object sender, EventArgs e)
{
    Randomize();
}
 
private void Form1_Load(object sender, EventArgs e)
{
    Num =  new Button[n, n];
    for (int i = 0; i < Num.GetLength(0); i++) 
        for (int j = 0; j < Num.GetLength(1); j++)
        {
            Num[i, j] = new Button();
            Num[i, j].Location = new Point(30 * i, 30 * j);
            Num[i, j].Size = new Size(30, 30);
          //  Num[i, j].Click += new EventHandler(Event);
            Controls.Add(Num[i, j]);
 
        }
}