...
this.Load += new System.EventHandler(this.Form1_Load);
...

private void Form1_Load(object sender, System.EventArgs e)
{
	string[] a = new string[ 4 ]{"A", "B", "C", "D"};
	string[] b = new string[ 4 ]{"1", "2", "3", "4"};
	
	Button btn;
	for(int i =  0 ; i <  4 ; i++)
	{
		for(int j =  0 ; j <  4 ; j++)
		{
			btn = new Button();
			btn.Name = "btn" + i.ToString() + j.ToString();
			btn.Width =  50 ;
			btn.Height =  50 ;
			btn.Location = new Point(i* 50 , j* 50 );
			btn.Text = a[i] + b[j];
			btn.CreateControl();
			btn.FlatStyle = System.Windows.Forms.FlatStyle.System;
			btn.Click += new System.EventHandler(this.BtnClick);
			
			Form1.ActiveForm.Controls.Add(btn);
		}
	}
}