public partial class TestControlDrag : Form{/// <summary>/// 该指标指示被拖动的对象是否进入了控件的边界/// </summary>bool bMouseDown;public TestControlDrag(){InitializeComponent();// 默认为 false,即不接受用户拖动到其上的控件this.groupBox1.AllowDrop = true;this.groupBox2.AllowDrop = true;// 拖动对象进入控件边界时触发this.groupBox1.DragEnter += new DragEventHandler(groupBox_DragEnter);this.groupBox2.DragEnter += new DragEventHandler(groupBox_DragEnter);// 完成拖动时触发this.groupBox1.DragDrop += new DragEventHandler(groupBox_DragDrop);this.groupBox2.DragDrop += new DragEventHandler(groupBox_DragDrop);}private void TestControlDrag_Load(object sender, EventArgs e){CreateControls();}/// <summary>/// 生成一定数量的控件,本例中使用 Button/// 注册 Button 的鼠标点击事件/// </summary>private void CreateControls(){int x = 15;int y = 15;Button btn = null;for (int i = 1; i <= 15; i++){btn = new Button();btn.Left = x;btn.Top = y;btn.Text = "Button " + i;btn.Width = 100;btn.Height = 50;x += btn.Width + 15;if (btn.Width > groupBox1.Width - x){x = 15;y += btn.Height + 15;}btn.AllowDrop = true; // 默认为 false,即不可拖动btn.MouseDown += new MouseEventHandler(btn_MouseDown);this.groupBox1.Controls.Add(btn);}}/// <summary>/// 拖动对象进入本控件的边界/// </summary>void groupBox_DragEnter(object sender, DragEventArgs e){e.Effect = DragDropEffects.Move;bMouseDown = true;}/// <summary>/// 拖放操作完成/// </summary>void groupBox_DragDrop(object sender, DragEventArgs e){if (bMouseDown){// 从事件参数 DragEventArgs 中获取被拖动的元素Button btn = (Button)e.Data.GetData(typeof(Button));GroupBox grp = (GroupBox)btn.Parent;grp.Controls.Remove(btn);((GroupBox)sender).Controls.Add(btn);RefreshControls(new Control[] { grp, (GroupBox)sender });bMouseDown = false;}}/// <summary>/// 按下鼠标后即开始执行拖放操作/// 这里指定了拖放操作的最终效果为一个枚举值: Move/// </summary>void btn_MouseDown(object sender, MouseEventArgs e){Button btn = (Button)sender;btn.DoDragDrop(btn, DragDropEffects.Move);}/// <summary>/// 对控件中的项进行排列/// </summary>private void RefreshControls(Control[] p){foreach (Control control in p){int x = 15;int y = 15;Button btn = null;foreach (Control var in control.Controls){btn = var as Button;btn.Left = x;btn.Top = y;x += btn.Width + 15;if (btn.Width > control.Width - x){x = 15;y += btn.Height + 15;}}}}}