在richtextbox里實(shí)現(xiàn)一個(gè)復(fù)制功能， 在控件的KeyDown事件中只能捕獲 contrl，在按下control的時(shí)候捕獲不到C，改用下面的方法

 PRivate void OnLoad()        {            rtbProgressInfo.PreviewKeyDown += OnPreviewKeyDown;            rtbProgressInfo.KeyDown += OnKeyDown;        }        private void OnPreviewKeyDown(object sender, PreviewKeyDownEventArgs e)        {            if (e.Control)            {                e.IsInputKey = true;            }        }        private void OnKeyDown(object sender, KeyEventArgs e)        {            if (e.Control && e.KeyCode == Keys.C)            {                try                {                    Clipboard.Clear();                    Clipboard.SetText(rtbProgressInfo.SelectedText.Trim());                }                catch (Exception ex)                {                    // log                }            }        }