C# 文本框 TextChanged 延时触发

public partial class DelayTextBox : TextBox
    {
        #region private globals

        private System.Timers.Timer DelayTimer; // used for the delay
        private bool TimerElapsed = false; // if true OnTextChanged is fired.
        private bool KeysPressed = false; // makes event fire immediately if it wasn't a keypress
        
        
        #endregion

        #region object model

        // Delay property
        private int delayTime = 3000;

        public int DelayTime
        {
            get { return delayTime; }
            set { delayTime = value; }
        }
        
        #endregion

        #region ctor

        public DelayTextBox()
        {
            InitializeComponent();

            // Initialize Ti