C# デバウンス(検索用)

System.Threading.Timer _timer = new System.Threading.Timer(x => {
    Invoke(new Action(() => { xxx(); })); 
});
textBox1.TextChanged += (s, e) => {
    _timer.Change(500, Timeout.Infinite);
};

System.Threading.Timer _timer = new System.Threading.Timer(x => {

Invoke(new Action(() => { xxx(); }));

});

textBox1.TextChanged += (s, e) => {

_timer.Change(500, Timeout.Infinite);

};