TreeList拖放数据到GridControl

拖放操作可以简化界面设计，提高工作效率。操作效果如下：

TreeList拖放数据到GridControl的步骤如下：

（1）设TreeList和GridControl的AllowDrop为ture，默认是不允许拖放的；

（2）定义数据实体，初始化并绑定数据；

（3）在TreeList按下时，获取其位置信息，主要是为了对击中的条目进行判断其是否允许被拖放（本例中未详细判断）；

（4）在TreeList移动时，获取移动的条目的信息，这里可以是传递任意对象；

（5）在GridControl进入时，获取其位置信息，主要是为了对击中的条目进行判断其是否允许拖放（本例中未详细判断）；

（6）在GridControl松开时，将拖放传递的对象绑定到GridControl数据源中。

代码如下：

using DevExpress.XtraEditors;
using DevExpress.XtraGrid.Views.Grid.ViewInfo;
using DevExpress.XtraTreeList;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;

namespace DragDropSample
{
    public partial class Form1 : XtraForm
    {
        /// <summary>
        /// TreeList点击信息
        /// </summary>
        private TreeListHitInfo _treeListHitInfo;

        /// <summary>
        /// Grid点击信息
        /// </summary>
        private GridHitInfo _gridHitInfo;

        public Form1()
        {
            InitializeComponent();

            //设置允许拖放
            this.treeList1.AllowDrop = true;
            this.gridControl1.AllowDrop = true;

            //绑定数据
            this.treeList1.ParentFieldName = "Pid";
            this.treeList1.KeyFieldName = "Id";
            this.treeList1.DataSource = GetTreeData();

            this.gridControl1.DataSource = null;
        }

        // 第一步，treeList按下，获取点击信息
        private void treeList1_MouseDown(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left && Control.ModifierKeys == Keys.None)
            {
                _treeListHitInfo = (sender as TreeList)?.CalcHitInfo(e.Location);
            }
            else
            {
                _treeListHitInfo = null;
            }
        }

        //第二步，treeList移动，设置拖放数据和效果
        private void treeList1_MouseMove(object sender, MouseEventArgs e)
        {
            if (e.Button == System.Windows.Forms.MouseButtons.Left && _treeListHitInfo != null && _treeListHitInfo.HitInfoType == HitInfoType.Cell)
            {
                Size size = SystemInformation.DragSize;
                Rectangle dragRect = new Rectangle(new Point(_treeListHitInfo.MousePoint.X - size.Width / 2, _treeListHitInfo.MousePoint.Y - size.Height / 2), size);

                if (dragRect.Contains(new Point(e.X, e.Y))) return;

                //拖放传递的数据可以是任意对象
                NodeRow nodeRow = (NodeRow)(sender as TreeList)?.GetRow(_treeListHitInfo.Node.Id);
                treeList1.DoDragDrop(nodeRow, DragDropEffects.Copy);
                DevExpress.Utils.DXMouseEventArgs.GetMouseArgs(e).Handled = false;
            }
        }

        //第三步，进入gridControl，获取位置，设置效果
        private void gridControl1_DragOver(object sender, DragEventArgs e)
        {
            _gridHitInfo = this.gridView1.CalcHitInfo(gridControl1.PointToClient(new Point(e.X, e.Y)));
            e.Effect = DragDropEffects.Copy;
        }

        //第四步，松开鼠标，绑定数据
        private void gridControl1_DragDrop(object sender, DragEventArgs e)
        {
            string type = string.Empty;
            object obj = e.Data.GetData(typeof(NodeRow));
            NodeRow nodeRow = (NodeRow)obj;
            List<NodeRow> list = (List<NodeRow>)this.gridControl1.DataSource ?? new List<NodeRow>();
            list.Add(nodeRow);
            this.gridControl1.DataSource = list;
            this.gridControl1.RefreshDataSource();
        }

        /// <summary>
        /// 初始化数据
        /// </summary>
        /// <returns></returns>
        private List<NodeRow> GetTreeData()
        {
            NodeRow nodeRow1 = new NodeRow() { Pid = "-1", Id = "1", Name = "四川" };
            NodeRow nodeRow2 = new NodeRow() { Pid = "1", Id = "2", Name = "成都" };
            NodeRow nodeRow3 = new NodeRow() { Pid = "1", Id = "3", Name = "绵阳" };
            NodeRow nodeRow4 = new NodeRow() { Pid = "-1", Id = "4", Name = "湖北" };
            NodeRow nodeRow5 = new NodeRow() { Pid = "4", Id = "5", Name = "武汉" };
            var nodeRows = new List<NodeRow>() { nodeRow1, nodeRow2, nodeRow3, nodeRow4, nodeRow5 };
            return nodeRows;
        }
    }

    /// <summary>
    /// 自定义对象
    /// </summary>
    public class NodeRow
    {
        public string Pid { get; set; }

        public string Id { get; set; }

        public string Name { get; set; }
    }
}