treeView without checkbox

参考文档：

http://dotnetfollower.com/wordpress/2011/05/winforms-treeview-hide-checkbox-of-treenode/

实现效果：

1. 子节点不带checkbox 2. 在子节点前面绘图

实现过程：

1. 继承treeNode

 public class HiddenCheckBoxTreeNode : TreeNode
    {
        private Color _NodeColor;
        public Color NodeColor
        {
            get { return _NodeColor; }
            set { _NodeColor = value; }
            
        }

        private int _Opacity;
        public int Opacity
        {
            get { return _Opacity; }
            set { 
                if (value>=0 && value <= 255)
                {
                    _Opacity = value;
                }
            }

        }
        public HiddenCheckBoxTreeNode() { }
        public HiddenCheckBoxTreeNode(string text) : base(text) { }
        public HiddenCheckBoxTreeNode(string text, Color color, int opacity) : base(text) { this._NodeColor = color; this._Opacity = opacity; }
        public HiddenCheckBoxTreeNode(string text, TreeNode[] children) : base(text, children) { }
        public HiddenCheckBoxTreeNode(string text, int imageIndex, int selectedImageIndex) : base(text, imageIndex, selectedImageIndex) { }
        public HiddenCheckBoxTreeNode(string text, int imageIndex, int selectedImageIndex, TreeNode[] children) : base(text, imageIndex, selectedImageIndex, children) { }
        protected HiddenCheckBoxTreeNode(SerializationInfo serializationInfo, StreamingContext context) : base(serializationInfo, context) { }
    }

2. 

public class MixedCheckBoxesTreeView : TreeView
{
    /// <summary>
    /// Specifies the attributes of a node
    /// </summary>
    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
    public struct TV_ITEM
    {
        public int    Mask;
        public IntPtr ItemHandle;
        public int    State;
        public int    StateMask;
        public IntPtr TextPtr;
        public int    TextMax;
        public int    Image;
        public int    SelectedImage;
        public int    Children;
        public IntPtr LParam;
    }
 
    public const int TVIF_STATE          = 0x8;
    public const int TVIS_STATEIMAGEMASK = 0xF000;
 
    public const int TVM_SETITEMA = 0x110d;
    public const int TVM_SETITEM  = 0x110d;
    public const int TVM_SETITEMW = 0x113f;
 
    public const int TVM_GETITEM  = 0x110C;
 
    [DllImport("user32.dll", CharSet = CharSet.Auto)]
    public static extern IntPtr SendMessage(HandleRef hWnd, int msg, int wParam, ref TV_ITEM lParam);
 
    protected override void WndProc(ref Message m)
    {
        base.WndProc(ref m);
 
        // trap TVM_SETITEM message
        if (m.Msg == TVM_SETITEM || m.Msg == TVM_SETITEMA || m.Msg == TVM_SETITEMW)
            // check if CheckBoxes are turned on
            if (CheckBoxes)
            {
                // get information about the node
                TV_ITEM tv_item = (TV_ITEM)m.GetLParam(typeof(TV_ITEM));
                HideCheckBox(tv_item);
            }
    }   
 
    protected void HideCheckBox(TV_ITEM tv_item)
    {
        if (tv_item.ItemHandle != IntPtr.Zero)
        {
            // get TreeNode-object, that corresponds to TV_ITEM-object
            TreeNode currentTN = TreeNode.FromHandle(this, tv_item.ItemHandle);
 
            HiddenCheckBoxTreeNode hiddenCheckBoxTreeNode = currentTN as HiddenCheckBoxTreeNode;
            // check if it's HiddenCheckBoxTreeNode and
            // if its checkbox already has been hidden
 
            if(hiddenCheckBoxTreeNode != null)
            {
                HandleRef treeHandleRef = new HandleRef(this, Handle);
 
                // check if checkbox already has been hidden
                TV_ITEM currentTvItem    = new TV_ITEM();
                currentTvItem.ItemHandle = tv_item.ItemHandle;
                currentTvItem.StateMask  = TVIS_STATEIMAGEMASK;
                currentTvItem.State      = 0;
 
                IntPtr res = SendMessage(treeHandleRef, TVM_GETITEM, 0, ref currentTvItem);
                bool needToHide = res.ToInt32() > 0 && currentTvItem.State != 0;
 
                if (needToHide)
                {
                    // specify attributes to update
                    TV_ITEM updatedTvItem    = new TV_ITEM();
                    updatedTvItem.ItemHandle = tv_item.ItemHandle;
                    updatedTvItem.Mask       = TVIF_STATE;
                    updatedTvItem.StateMask  = TVIS_STATEIMAGEMASK;
                    updatedTvItem.State      = 0;
 
                    // send TVM_SETITEM message
                    SendMessage(treeHandleRef, TVM_SETITEM, 0, ref updatedTvItem);
                }
            }
        }
    }
 
    protected override void OnBeforeCheck(TreeViewCancelEventArgs e)
    {
        base.OnBeforeCheck(e);
 
        // prevent checking/unchecking of HiddenCheckBoxTreeNode,
        // otherwise, we will have to repeat checkbox hiding
        if (e.Node is HiddenCheckBoxTreeNode)
            e.Cancel = true;
    }
}

3. 添加子节点

 HiddenCheckBoxTreeNode node2Add = new HiddenCheckBoxTreeNode(renderItemTxt, color, opacity);
 seletedNode.Nodes.Add(node2Add);

4. 对treeview添加绘图事件

 toc.DrawMode = TreeViewDrawMode.OwnerDrawText;
 toc.DrawNode +=new DrawTreeNodeEventHandler(toc_DrawNode);

void toc_DrawNode(object sender, DrawTreeNodeEventArgs e)
        {
            e.DrawDefault = true;
            //画颜色
            Rectangle rect = e.Bounds;
            Rectangle colorRect = new Rectangle(rect.Left - 15, rect.Top, 12, 12);
            Main.UserCtr.HiddenCheckBoxTreeNode hiddenNode = e.Node as Main.UserCtr.HiddenCheckBoxTreeNode;
            
            if (hiddenNode != null && e.Node.Level == 2)
            {
                //Color nodeColor = Common.ColorHelper.SetColorOpacity(hiddenNode.NodeColor, hiddenNode.Opacity);
                using (SolidBrush brush = new SolidBrush(hiddenNode.NodeColor))
                {
                    e.Graphics.FillRectangle(brush, colorRect);
                }
            }
        }