treeviewex.cs

JAVA的精彩实例

namespace feiyun0112.cnblogs.com.CSDNReader.Controls
{
	using System;
	using System.Drawing;
	using System.Runtime.CompilerServices;
	using System.Text;
	using System.Windows.Forms;
	using System.Runtime.InteropServices;

	public class TreeViewEx : TreeView
	{
        private int _updateCount;
        private const int CCM_FIRST = 0x2000;
        private const int CCM_SETVERSION = 0x2007;
        private const int CDDS_ITEMPREPAINT = 0x10001;
        private const int CDRF_NOTIFYSUBITEMDRAW = 0x20;
        private const int NM_CUSTOMDRAW = -12;
        private const int NM_FIRST = 0;
        private const int OCM_NOTIFY = 0x204e;

		[StructLayout(LayoutKind.Sequential)]
			internal struct NMCUSTOMDRAW
		{
			public NMHDR hdr;
			public int dwDrawStage;
			public IntPtr hdc;
			public Rectangle rc;
			public int dwItemSpec;
			public int uItemState;
			public IntPtr lItemlParam;
		}

		
		[StructLayout(LayoutKind.Sequential)]
			internal struct NMHDR
		{
			public IntPtr hwndFrom;
			public int idfrom;
			public int code;
		}

		public delegate string DelegateGetNodeInfo(TreeNode node);
		public event DelegateGetNodeInfo GetNodeInfo;
 
        public void BeginUpdate()
        {
            base.BeginUpdate();
            this._updateCount++;
        }

        private void BuildState(TreeNode node, StringBuilder sb)
        {
            if (node.IsSelected)
            {
                sb.Append('S');
            }
            if (!node.IsExpanded)
            {
                sb.Append('-');
            }
            else
            {
                sb.Append('+');
                foreach (TreeNode n in node.Nodes)
                {
                    this.BuildState(n, sb);
                }
            }
        }

        public void EndUpdate()
        {
            if (this._updateCount > 0)
            {
                this._updateCount--;
            }
            base.EndUpdate();
        }

        public string GetState()
        {
            StringBuilder sb = new StringBuilder();
            this.BuildState(base.Nodes[0], sb);
            return sb.ToString();
        }

        protected override void OnCreateControl()
        {
            base.OnCreateControl();
            Message msg = Message.Create(base.Handle, 0x2007, new IntPtr(5), IntPtr.Zero);
            this.DefWndProc(ref msg);
        }

        public void RestoreState(string state)
        {
            if (state != null)
            {
                int index = 0;
                this.RestoreState(state, ref index, base.Nodes[0]);
                if (base.SelectedNode != null)
                {
                    base.SelectedNode.EnsureVisible();
                }
            }
        }

        private void RestoreState(string state, ref int stateIndex, TreeNode node)
        {
            if (stateIndex < state.Length)
            {
                char c = state[stateIndex++];
                switch (c)
                {
                    case 'S':
                        base.SelectedNode = node;
                        c = state[stateIndex++];
                        break;

                    case '-':
                        node.Collapse();
                        return;
                }
                if (c == '+')
                {
                    node.Expand();
                    foreach (TreeNode n in node.Nodes)
                    {
                        this.RestoreState(state, ref stateIndex, n);
                    }
                }
            }
        }

        public void TreeViewPaintNodeInfo(Rectangle rc)
        {
            if (rc != Rectangle.Empty)
            {
                TreeNode node = base.GetNodeAt(rc.Location.X + 1, rc.Location.Y + 1);
                if ((node != null) && !node.IsEditing)
                {
                    string strText = this.GetNodeInfo(node);
                    if (strText != null)
                    {
                        long relXpos = node.Bounds.X + node.Bounds.Width;
                        long xpos = rc.X + relXpos;
                        long ypos = rc.Y;
                        Brush brush = new SolidBrush(this.BackColor);
                        using (Graphics g = Graphics.FromHwnd(base.Handle))
                        {
                            g.FillRectangle(brush, (float)xpos, (float)ypos, (float)(base.Width - relXpos), (float)node.Bounds.Height);
                            g.DrawString(" (" + strText + ")", this.Font, Brushes.Blue, (float)xpos, (float)ypos, StringFormat.GenericTypographic);
                        }
                    }
                }
            }
        }

        protected override void WndProc(ref Message m)
        {
            if (((m.Msg == 0x204e) && (this.GetNodeInfo != null)) && (this._updateCount == 0))
            {
                NMHDR hdr = (NMHDR)m.GetLParam(typeof(NMHDR));
                if ((hdr.code == -12) && (hdr.hwndFrom == base.Handle))
                {
                    NMCUSTOMDRAW customDraw = (NMCUSTOMDRAW)m.GetLParam(typeof(NMCUSTOMDRAW));
                    if (customDraw.dwDrawStage == 0x10001)
                    {
                        this.TreeViewPaintNodeInfo(customDraw.rc);
                        m.Result = IntPtr.Zero;
                    }
                    else
                    {
                        m.Result = (IntPtr)0x20;
                    }
                }
            }
            base.WndProc(ref m);
        }


		 
	}
}