using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace OpcUaHelper.Forms
{
    /// <summary>
    /// 无闪烁的树节点控件，结果还是没有实现
    /// </summary>
    public class TreeViewEx : TreeView
    {
        /// <summary>
        /// 实例化一个新的控件
        /// </summary>
        public TreeViewEx()
        {
            // 开启双缓冲
            SetStyle(ControlStyles.OptimizedDoubleBuffer | ControlStyles.AllPaintingInWmPaint, true);

            // Enable the OnNotifyMessage event so we get a chance to filter out 
            // Windows messages before they get to the form's WndProc
            SetStyle(ControlStyles.EnableNotifyMessage, true);
        }

        /// <summary>
        /// 通知
        /// </summary>
        /// <param name="m"></param>
        protected override void OnNotifyMessage(Message m)
        {
            //Filter out the WM_ERASEBKGND message
            if (m.Msg != 0x14)
            {
                base.OnNotifyMessage(m);
            }

        }

        //protected override void WndProc(ref Message m)
        //{
        //    if (m.Msg == 0x0014) // 禁掉清除背景消息
        //        return;
        //    base.WndProc(ref m);
        //}
    }
}