简单问题：|=这个符号是什么意思？请高手指教！解决即结帐！在线等...

/*
insert license info here
*/
using System;namespace Business.domain
{
    /// <summary>
    /// Generated by MyGeneration using the IBatis Object Mapping template
    /// </summary>
    [Serializable]
    public sealed class Mistable001
    {
        #region Private Members
        private bool _isChanged;
        private bool _isDeleted;
        private float _mistable001id;
        private string _misfield001a00;
        private string _misfield001a01;
        private string _misfield001a02;
        private string _misfield001a03;
        private string _misfield001a04;
        private string _misfield001a05;
        private string _misfield001a06;
        private string _misfield001a07;
        private DateTime _misfield001a08;
        private string _misfield001a09;
        private string _misfield001a10;
        private string _misfield001a11;
        private DateTime _misfield001a12;
        private string _misfield001a13;
        private string _misfield001a14;
        private string _misfield001a15;
        private string _misfield001a16;
        private string _misfield001a17;
        private string _misfield001a18;
        private string _misfield001a19;
        private string _misfield001a20;
        private string _misfield001a21;
        private string _misfield001a22;
        private string _misfield001a23;
        private string _misfield001a24;
        private string _misfield001a25;
        private string _misfield001a26;
        private string _misfield001a27;
        private DateTime _misfield001a28;
        private DateTime _misfield001a29;
        private string _misfield001a30;
        private string _misfield001a31;
        private string _misfield001a32;
        private string _misfield001a33;
        private string _misfield001a34;
        private DateTime _misfield001a35;
        private string _misfield001a36;
        private DateTime _misfield001a37;
        private string _misfield001a38;
        private DateTime _misfield001a39;
        private string _misfield001a40;
        private string _misfield001a41;
        private string _misfield001a42;
        #endregion        #region Default ( Empty ) Class Constuctor
        /// <summary>
        /// default constructor
        /// </summary>
        public Mistable001()
        {
            _mistable001id = 0;
            _misfield001a00 = null;
            _misfield001a01 = null;
            _misfield001a02 = null;
            _misfield001a03 = null;
            _misfield001a04 = null;
            _misfield001a05 = null;
            _misfield001a06 = null;
            _misfield001a07 = null;
            _misfield001a08 = new DateTime();
            _misfield001a09 = null;
            _misfield001a10 = null;
            _misfield001a11 = null;
            _misfield001a12 = new DateTime();
            _misfield001a13 = null;
            _misfield001a14 = null;
            _misfield001a15 = null;
            _misfield001a16 = null;
            _misfield001a17 = null;
            _misfield001a18 = null;
            _misfield001a19 = null;
            _misfield001a20 = null;
            _misfield001a21 = null;
            _misfield001a22 = null;
            _misfield001a23 = null;
            _misfield001a24 = null;
            _misfield001a25 = null;
            _misfield001a26 = null;
            _misfield001a27 = null;
            _misfield001a28 = new DateTime();
            _misfield001a29 = new DateTime();
            _misfield001a30 = null;
            _misfield001a31 = null;
            _misfield001a32 = null;
            _misfield001a33 = null;
            _misfield001a34 = null;
            _misfield001a35 = new DateTime();
            _misfield001a36 = null;
            _misfield001a37 = new DateTime();
            _misfield001a38 = null;
            _misfield001a39 = new DateTime();
            _misfield001a40 = null;
            _misfield001a41 = null;
            _misfield001a42 = null;
        }
        #endregion // End of Default ( Empty ) Class Constuctor        #region Public Properties        /// <summary>
        /// 本地记录唯一标识(自动加一)
        /// </summary>
        public float Mistable001id
        {
            get { return _mistable001id; }
            set { _isChanged |= (_mistable001id != value); _mistable001id = value; }
        }        /// <summary>
        /// 分布式系统唯一标识(数据库安装地的单位编码)
        /// </summary>
        public string Misfield001a00
        {
            get { return _misfield001a00; }
            set
            {
                if (value != null && value.Length > 12)
                    throw new ArgumentOutOfRangeException("Invalid value for Misfield001a00", value, value.ToString());                _isChanged |= (_misfield001a00 != value); _misfield001a00 = value;
            }
        }
         //中间略
       /// <summary>
        /// Returns whether or not the object has changed it's values.
        /// </summary>
        public bool IsChanged
        {
            get { return _isChanged; }
        }        /// <summary>
        /// Returns whether or not the object has changed it's values.
        /// </summary>
        public bool IsDeleted
        {
            get { return _isDeleted; }
        }        #endregion
    }
}
我用代码生成器生成代码，  _isChanged |= (_misfield001a00 != value)，这句代码里|=这个符号不知道是什么意思？请高手指教！