继上次定制TreeView控件，实现节点样式自定义及节点级别的单选、复选后继续对TreeView控件，这次实现的功能是树节点可以按Ctrl/Shift键多选和树节点的拖动。相对于上次的代码，这次主要新增加也以下几个属性和方法：
- IsMultiSelect属性：树是否需要使用多选功能
- SelectedNodeList属性：多选时被选中的节点的集合
- TreeNodeCanAcceptDragedHandler事件：拖动时用来判断目标节点是否接受拖动
- IsNodeCanAcceptDragHandler事件：拖动成功后要执行的事件，一般用来将新的关系持久化到数据库或其它地方。
实现比较简单，各位直接看代码吧。
扩展树的代码
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Windows.Forms;
using GADPlatSystem.Navigate;
namespace GADPlatSystem.Tools
{
///<summary>
/// 导航树控件
///</summary>
[DesignTimeVisible(true)]
[Serializable]
public class GTreeView : TreeView
{
#region 成员变量
///<summary>
/// 存储多选时选择的节点
///</summary>
private IList<TreeNode> selectedNodeList = new List<TreeNode>();
///<summary>
/// 当前节点
///</summary>
private TreeNode currentNode = null;
#endregion
#region 属性
///<summary>
/// 是否是多选
///</summary>
public bool IsMultiSelect { get; set; }
///<summary>
/// 选择的节点的集合
///</summary>
public IList<TreeNode> SelectedNodeList
{
get { return selectedNodeList; }
}
#endregion
#region Delegate & Event
///<summary>
/// 节点被拖动后要处理事件的Delegate
///</summary>
///<param name="sourceNode">被拖动的节点</param>
///<param name="targetNode">目标节点</param>
public delegate void OnDragNodeSucceed(TreeNode sourceNode, TreeNode targetNode);
///<summary>
/// 判断目标节点是否接受拖动的Delegate
///</summary>
///<param name="targetNode"></param>
///<returns></returns>
public delegate bool IsNodeCanAcceptDrag(TreeNode targetNode);
///<summary>
/// 节点被拖动后要处理事件
///</summary>
public event OnDragNodeSucceed TreeNodeCanAcceptDragedHandler;
///<summary>
/// 判断目标节点是否接受拖动的事件处理
///</summary>
public event IsNodeCanAcceptDrag IsNodeCanAcceptDragHandler;
#endregion
#region 类函数
///<summary>
/// 构造函数
///</summary>
public TreeViewExt()
: base()
{
this.DrawMode = TreeViewDrawMode.OwnerDrawText;
}
///<summary>
/// 鼠标单击事件
///</summary>
///<param name="e">TreeNodeMouseClickEventArgs对象类</param>
protected override void OnNodeMouseClick(TreeNodeMouseClickEventArgs e)
{
this.SelectedNode = e.Node;
var isSingleSelected = false;
// 如果是多选，则根据按钮情况设置节点的选择状态
if (IsMultiSelect)
{
if (!(SelectedNodeList.Count == 1 && SelectedNodeList[0] == SelectedNode))
{
if ((Control.ModifierKeys & Keys.Control) != 0 || e.Button == MouseButtons.Right)
{
ctrlMultiSelectNodes(SelectedNode, e.Button == MouseButtons.Right);
}
else if ((Control.ModifierKeys & Keys.Shift) != 0)
{
shiftMultiSelectNodes(SelectedNode, e.Button == MouseButtons.Right);
}
else
{
isSingleSelected = true;
singleSelectNode(SelectedNode);
}
}
isSingleSelected = true;
}
else
{
singleSelectNode(SelectedNode);
setCurrentNode(SelectedNode);
}
this.Invalidate();
}
///<summary>
/// 重绘,主要是在Checkbox/RadioButton前面有图片
///</summary>
///<param name="e">DrawTreeNodeEventArgs对象类</param>
protected override void OnDrawNode(DrawTreeNodeEventArgs e)
{
if (e.Bounds.X == -1)
return;
e.DrawDefault = false;
Font font = this.Font;
if (e.Node.NodeFont != null) font = e.Node.NodeFont;
Color color = this.ForeColor;
if (SelectedNodeList.Contains(e.Node))
{
color = SystemColors.HighlightText;
}
else if (e.Node.ForeColor != Color.Empty)
{
color = e.Node.ForeColor;
}
Graphics g = e.Graphics;
Rectangle textBounds = new Rectangle();
GTreeNode extNode = e.Node as GTreeNode;
textBounds.X = e.Bounds.X;
textBounds.Y = e.Bounds.Y;
textBounds.Width = e.Bounds.Width;
textBounds.Height = e.Bounds.Height;
// 绘制节点的文本
if (SelectedNodeList.Contains(e.Node))
{
g.FillRectangle(SystemBrushes.Highlight, textBounds);
ControlPaint.DrawFocusRectangle(g, textBounds, color, SystemColors.Highlight);
TextRenderer.DrawText(g, e.Node.Text, font, textBounds, color, TextFormatFlags.Default);
}
else
{
g.FillRectangle(SystemBrushes.Window, textBounds);
TextRenderer.DrawText(g, e.Node.Text, font, textBounds, color, TextFormatFlags.Default);
}
}
//控件初始化
private void InitializeComponent()
{
this.SuspendLayout();
//
// GTreeViewExt
//
this.Indent = 25;
this.ItemHeight = 25;
this.ResumeLayout(false);
}
#endregion
#region 鼠标拖动节点移动
///<summary>
/// 拖动节点移动,在鼠标拖放操作结束时发生
///</summary>
///<param name="drgevent">DragEventArgs对象</param>
protected override void OnDragDrop(DragEventArgs drgevent)
{
base.OnDragDrop(drgevent);
var moveNode = (TreeNode)drgevent.Data.GetData(typeof(TreeNode));
//根据鼠标坐标确定要移动到的目标节点
Point point = this.PointToClient(new Point(drgevent.X, drgevent.Y));
var targetNode = this.GetNodeAt(point);
// 如果目标节点不接受拖动，则返回
if (IsNodeCanAcceptDragHandler != null)
{
if (!IsNodeCanAcceptDragHandler(targetNode))
{
return;
}
}
// 确定落下的节点不是被拖拽节点本身或者被拖拽节点的子节点
if (!moveNode.Equals(targetNode) && !containsNode(moveNode, targetNode))
{
var newMoveNode = (TreeNode)moveNode.Clone();
targetNode.Nodes.Insert(targetNode.Index, newMoveNode);
//更新当前拖动的节点选择
this.SelectedNode = newMoveNode;
//移除拖放的节点
moveNode.Remove();
moveNode = newMoveNode;
newMoveNode.Expand();
if (TreeNodeCanAcceptDragedHandler != null)
{
TreeNodeCanAcceptDragedHandler(moveNode, targetNode);
}
}
}
///<summary>
/// 拖动节点移动,在用鼠标将某项拖动到该控件的工作区时发生
///</summary>
///<param name="drgevent">DragEventArgs对象</param>
protected override void OnDragEnter(DragEventArgs drgevent)
{
base.OnDragEnter(drgevent);
if (drgevent.Data.GetDataPresent(typeof(TreeNode)))
{
drgevent.Effect = DragDropEffects.Move;
}
else
{
drgevent.Effect = DragDropEffects.None;
}
}
///<summary>
/// 拖动节点移动，在用户开始拖动项时发生
///</summary>
///<param name="e">ItemDragEventArgs对象</param>
protected override void OnItemDrag(ItemDragEventArgs e)
{
base.OnItemDrag(e);
if (e.Button == MouseButtons.Left)
{
DoDragDrop(e.Item, DragDropEffects.Move);
}
}
#endregion 鼠标拖动节点移动
#region Private Methods
///<summary>
/// 按ctrl键多选的方法
///</summary>
///<param name="node"></param>
///<param name="mustSelect"></param>
private void ctrlMultiSelectNodes(TreeNode node, bool mustSelect)
{
if (SelectedNodeList.Contains(node) && !mustSelect)
{
SelectedNodeList.Remove(node);
setCurrentNode((TreeNode)SelectedNodeList[SelectedNodeList.Count - 1]);
}
else if (!mustSelect)
{
SelectedNodeList.Add(node);
setCurrentNode(node);
}
}
///<summary>
/// 按shift键多选的方法
///</summary>
///<param name="node"></param>
///<param name="mustSelect"></param>
private void shiftMultiSelectNodes(TreeNode node, bool mustSelect)
{
if (mustSelect)
{
return;
}
if (SelectedNodeList.Contains(node))
{
SelectedNodeList.Remove(node);
setCurrentNode((TreeNode)SelectedNodeList[SelectedNodeList.Count - 1]);
}
else
{
if (node.Parent == currentNode.Parent)
{
TreeNode addNode = node;
for (int i = System.Math.Abs(currentNode.Index - node.Index); i > 0; i--)
{
if (!SelectedNodeList.Contains(addNode))
{
SelectedNodeList.Add(addNode);
}
addNode = currentNode.Index > node.Index ? addNode.NextNode : addNode.PrevNode;
}
setCurrentNode(node);
}
else
{
singleSelectNode(SelectedNode);
}
}
}
///<summary>
/// single select
///</summary>
///<param name="node"></param>
private void singleSelectNode(TreeNode node)
{
SelectedNodeList.Clear();
SelectedNodeList.Add(node);
setCurrentNode(node);
}
///<summary>
/// Set current node
///</summary>
///<param name="node"></param>
private void setCurrentNode(TreeNode node)
{
//if (isMulSelect)
// SelectedNode = null;
if (currentNode != node)
{
currentNode = node as TreeNode;
}
}
///<summary>
/// 确定一个节点是否是另一个节点的祖先节点
///</summary>
///<param name="parentNode"></param>
///<param name="childNode"></param>
///<returns></returns>
private bool containsNode(TreeNode parentNode, TreeNode childNode)
{
if (childNode.Parent == null) return false;
if (childNode.Parent.Equals(parentNode)) return true;
return containsNode(parentNode, childNode.Parent);
}
#endregion
}
}
使用示例
private void Form1_Load(object sender, EventArgs e)
{
var gTreeView1 = new GTreeViewExt();
gTreeView1.AllowDrop = true;
gTreeView1.IsMultiSelect = true;
gTreeView1.TreeNodeDragedHandler += (source, target) =>
{ listBox1.Items.Add("将" + source.Text + "拖动到了" + target.Text); };
for (int i = 0; i < 10; i++)
{
var cNode = new TreeNode();
cNode.Tag = i;
cNode.Text = "Node" + i;
cNode.ImageIndex = 0;
cNode.SelectedImageIndex = 0;
gTreeView1.Nodes.Add(cNode);
for (int j = 0; j < i; j++)
{
var innerNode = new TreeNode();
innerNode.Tag = i;
innerNode.Text = "InnerNode" + i + "-" + j;
innerNode.ImageIndex = 0;
innerNode.SelectedImageIndex = 0;
cNode.Nodes.Add(innerNode);
}
}
gTreeView1.ExpandAll();
gTreeView1.Width = 400;
gTreeView1.Dock = DockStyle.Left;
Controls.Add(gTreeView1);
}