让FX1.1的NotifyIcon支持BalloonTip(2)

    在这个文章的(1)中，我本来打算完全自己实现一个支持Balloon Tip的NotifyIcon控件。后来发现实现NotifyIcon控件的大量代码都纠缠在事件的处理和包装上面，太没有写头了，简直就像打劫一样没有技术含量了。于是干脆一不做二不休，就用NotifyIcon Reflect出来的代码做基类来实现支持Balloon Tip得了。

    于是实现一个NotifyIconEx类继承至重新编译的NotifyIcon类，新的NotifyIcon只做了利于被继承的非常少量的修改。目前除了事件处理外，只添加了一个ShowBalloonTip方法，并重载了一下WndProc方法，至于BalloonTipTitle、BalloonTipMessage和BalloonTipIcon以及Timeout的属性支持都没有加，因为要加上也非常的容易了。

    派生类NotifyIconEx的代码如下：

using System;

namespace Birdshome
{
    /**//// <summary>
    /// Summary description for NotifyIconEx.
    /// </summary>
    public class NotifyIconEx : NotifyIcon
    {
        private const int WM_BALLOONTIPSHOWN = 0x0402;
        private const int WM_BALLOONTIPCLOSING = 0x0403;
        private const int WM_BALLOONTIPCLOSED = 0x0404;
        private const int WM_BALLOONTIPCLICKED = 0x0405;

        private static readonly object EVENT_BALLOONTIPSHOWN;
        private static readonly object EVENT_BALLOONTIPCLOSED;
        private static readonly object EVENT_BALLOONTIPCLICKED;

        static NotifyIconEx()
        {
            NotifyIconEx.EVENT_BALLOONTIPSHOWN = new object();
            NotifyIconEx.EVENT_BALLOONTIPCLOSED = new object();
            NotifyIconEx.EVENT_BALLOONTIPCLICKED = new object();
        }

        public NotifyIconEx()
        {
            //
            // TODO: Add constructor logic here
            //
        }

        public event EventHandler BalloonTipShown
        {
            add
            {
                this.Events.AddHandler(NotifyIconEx.EVENT_BALLOONTIPSHOWN, value);
            }
            remove
            {
                this.Events.RemoveHandler(NotifyIconEx.EVENT_BALLOONTIPSHOWN, value);
            }
        }

        public event EventHandler BalloonTipClosed
        {
            add
            {
                this.Events.AddHandler(NotifyIconEx.EVENT_BALLOONTIPCLOSED, value);
            }
            remove
            {
                this.Events.RemoveHandler(NotifyIconEx.EVENT_BALLOONTIPCLOSED, value);
            }
        }

        public event EventHandler BalloonTipClicked
        {
            add
            {
                this.Events.AddHandler(NotifyIconEx.EVENT_BALLOONTIPCLICKED, value);
            }
            remove
            {
                this.Events.RemoveHandler(NotifyIconEx.EVENT_BALLOONTIPCLICKED, value);
            }
        }

        public void ShowBalloonTip(InfoIcon infoIcon, string title, string message, uint timeout)
        {
            nid.uFlags = 0x0010;
            nid.dwInfoFlags = (int)infoIcon;
            nid.szInfo = message;
            nid.szInfoTitle = title;
            nid.uTimeoutOrVersion = timeout;
            base.UpdateIcon(true);
        }

        private void OnBalloonTipShown()
        {
            EventHandler handler = (EventHandler) base.Events[NotifyIconEx.EVENT_BALLOONTIPSHOWN];
            if (handler != null)
            {
                handler(this, EventArgs.Empty);
            }
        }

        private void OnBalloonTipClosed()
        {
            EventHandler handler = (EventHandler) base.Events[NotifyIconEx.EVENT_BALLOONTIPCLOSED];
            if (handler != null)
            {
                handler(this, EventArgs.Empty);
            }
        }

        private void OnBalloonTipClicked()
        {
            EventHandler handler = (EventHandler) base.Events[NotifyIconEx.EVENT_BALLOONTIPCLICKED];
            if (handler != null)
            {
                handler(this, EventArgs.Empty);
            }
        }

        protected override void WndProc(ref System.Windows.Forms.Message msg)
        {
            int msgId = msg.Msg;
            if ( msgId == 0x111 )
            {
                switch((int)msg.LParam)
                {
                    case WM_BALLOONTIPSHOWN:
                    {
                        this.OnBalloonTipShown();
                        break;
                    }
                    case WM_BALLOONTIPCLOSING:
                    {
                        this.OnBalloonTipClosed();
                        break;
                    }
                    case WM_BALLOONTIPCLOSED:
                    {
                        this.OnBalloonTipClosed();
                        break;
                    }
                    case WM_BALLOONTIPCLICKED:
                    {
                        this.OnBalloonTipClicked();
                        break;
                    }
                }
            }
            base.WndProc (ref msg);
        }
    }
}

    为了尽可能的利用原来的NotifyIcon中的代码，不做太大的改动。新的NotifyIcon中修改了UpdateIcon方法中uFlags的管理。原来的代码是在调用UpdateIcon时给uFlags赋值为0x0001(即：NIF_MESSAGE)，然后再通过一些判断通过|操作加入新的flag。现在把第一次赋值改为了：uFlags|=0x0001，目的是为了把ShowBalloonTip中对uFlags的赋值传递进取。但是如果在显示了Balloon Tip后，uFlags中仍然保持了0x0010(即：NIF_INFO)标志位，那么只要NotifyIcon中移执行UpdateIcon就会再次显示Balloon Tip。所以在UpdateIcon方法的最后，我们清除uFlags中的0x0010标识位，让uFlag ^= 0x0010;，就这样简单NotifyIcon即改造完毕。