public class Form1
{
    //計數變數，說明輸出了第N個Button
    private int count = 1;
    private void Form1_Load(System.Object sender, System.EventArgs e)
    {
        //窗體自身支援接受拖拽來的控制元件
        this.AllowDrop = true;
    }

    private void Button1_MouseDown(System.Object sender, System.Windows.Forms.MouseEventArgs e)
    {
        
 
//左鍵的話，標誌位為true（表示拖拽開始）
        if ((e.Button == System.Windows.Forms.MouseButtons.Left))
        {
            Button1.DoDragDrop(Button1, DragDropEffects.Copy | DragDropEffects.Move);
            //形成拖拽效果，移動+拷貝的組合效果
        }
    }

    private void Form1_DragEnter(System.Object sender, System.Windows.Forms.DragEventArgs e)
    {
        
 
//當Button被拖拽到WinForm上時候，滑鼠效果出現
        if ((e.Data.GetDataPresent(typeof(Button))))
        {
            e.Effect = DragDropEffects.Copy;
        }
    }

    private void Form1_DragDrop(System.Object sender, System.Windows.Forms.DragEventArgs e)
    {
        //拖放完畢之後，自動生成新控制元件
        Button btn = new
 
 Button();
        btn.Size = Button1.Size;
        btn.Location = this.PointToClient(new Point(e.X, e.Y));
        //用這個方法計算出客戶端容器介面的X，Y座標。否則直接使用X，Y是螢幕座標
        this.Controls.Add(btn);
        btn.Text = "按鈕" + count.ToString();
        count = count + 1;
    }
    public Form1()
    {
        DragDrop += Form1_DragDrop;
        DragEnter += Form1_DragEnter;
        Load += Form1_Load;
    }
}