获取QQ当前状态

/// <summary>
    /// 获取QQ当前状态（1：在线，0：不在线，-1：不存在）
    /// </summary>
    /// <param name="qq">qq号</param>
    /// <returns></returns>
    public static int GetQQState(long qq)
    {
        WebClient client = new WebClient();
        byte[] data;
        try { data = client.DownloadData("http://wpa.qq.com/pa?p=1:" + qq.ToString() + ":1"); }
        catch { data = new byte[0]; }
        switch (data.Length)
        {
            case 2329:
                return 1;
                break;
            case 2262:
                return 0;
                break;
            case 0:
                return -1;
                break;
            default:
                return -1;
                break;
        }
    }