WinForm 实现两个容器之间控件的拖动及排列(图文)

1. 启动程序,图如下:

2. 拖动 Button 后的效果如下:

3. 程序源代码如下:

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;
                    }
                }
            }
        }
    }