以前也研究过,始终没找到好的办法,看了微软Msdn上的解决方案,使用后发现存在较多漏洞,考虑的情况太少,如页面加载后没有提交,始终刷新,在同一浏览器打开多个各选项卡,每个选项卡打开同一页面或不同页面,以下是我的解决方案,
Code
public class RefreshServe : System.Web.UI.Page
{
private static ILog log = LogManager.GetLogger(typeof(RefreshServe));
private readonly string REFRESH_TICKET_NAME = "__RefreshTicketArray";
private readonly string HIDDEN_FIELD_NAME = "__RefreshHiddenField";
private readonly string HIDDEN_PAGE_GUID = "__RefreshPageGuid";
/// <summary>
/// 为True表示页面刷新,False为正常提交
/// </summary>
public bool IsPageRefreshed
{
get
{
if (IsPostBack && !CheckRefreshFlag())
{
log.Debug("刷新了页面");
return true;
}
else
{
log.Debug("正常提交");
return false;
}
}
}
/// <summary>
/// 呈现前更新标识
/// </summary>
/// <param name="e"></param>
protected override void OnPreRender(EventArgs e)
{
log.Debug("执行OnPreRender");
base.OnPreRender(e);
UpdateRefreshFlag();
}
/// <summary>
/// 更新标识,正常提交都删除该次提交的时间,并生产当前新的时间
/// </summary>
private void UpdateRefreshFlag()
{
#region Cookie模式
//注册页面唯一标识并返回
string pageGuid = SetCurPageGuid();
HttpCookie cookie = GetRefreshTicket();
if (cookie.Values.Count > 0)
{
cookie.Values.Remove(pageGuid);
log.Debug("当前清除的cookie变是:" + pageGuid);
}
string submitTime = DateTime.Now.ToString("hhmmss.fffff");
//当前提交时间保存到隐藏域
ClientScript.RegisterHiddenField(HIDDEN_FIELD_NAME, submitTime);
log.Debug("即将要新增的时间:submitTime:" + submitTime + " Guid:" + pageGuid.ToString());
cookie.Values.Add(pageGuid, submitTime);
log.Debug("UpdateRefreshFlag中当前Cookie中存在的记录数为:" + cookie.Values.Count);
for (int i = 0; i < cookie.Values.Count; i++)
log.Info("cookie[" + cookie.Values.GetKey(i) + "]:" + cookie.Values[i]);
Response.AppendCookie(cookie);
#endregion
}
/// <summary>
/// 验证是否刷新
/// </summary>
/// <returns></returns>
private bool CheckRefreshFlag()
{
HttpCookie cookie = GetRefreshTicket();
string pageGuid = GetCurPageGuid();
if (cookie.Values.Count > 0)
{
bool flag;
if (cookie.Values[pageGuid] != null)
flag = cookie.Values[pageGuid].IndexOf(GetCurSubmitTime()) > -1;
else
flag = true;//防止出现异常,总是可以提交
if (flag)
log.Debug("提交时间存在,可以提交");
else
log.Debug("无效的提交时间");
return flag;
}
return true;
}
/// <summary>
/// 得到已保存的提交时间,没有新建,有返回
/// </summary>
/// <returns></returns>
private HttpCookie GetRefreshTicket()
{
#region Cookie模式,返回值为Cookie
HttpCookie cookie;
if (Request.Cookies[REFRESH_TICKET_NAME] == null)
{
cookie = new HttpCookie(REFRESH_TICKET_NAME);
Response.AppendCookie(cookie);
log.Debug("Cookie不存在，初始化");
}
else
{
cookie = Request.Cookies[REFRESH_TICKET_NAME];
log.Debug("读取已存在的Cookie,当前Cookie中存在的记录数为:" + cookie.Values.Count + "具体有如下几条:");
for (int i = 0; i < cookie.Values.Count; i++)
log.Info("cookie[" + cookie.Values.GetKey(i) + "]:" + cookie.Values[i]);
}
return cookie;
#endregion
}
/// <summary>
/// 获取当前提交时间
/// </summary>
/// <returns></returns>
private string GetCurSubmitTime()
{
string submitTime = Request.Params[HIDDEN_FIELD_NAME] == null ? "" : Request.Params[HIDDEN_FIELD_NAME].ToString();
log.Debug("执行GetCurSubmitTime:submitTime为:" + submitTime);
return submitTime;
}
/// <summary>
/// 设置页面唯一标识,通过Guid标识来区分每个页面自己的提交时间
/// </summary>
private string SetCurPageGuid()
{
string guid;
if (!IsPostBack)
{
if (Request.Params[HIDDEN_PAGE_GUID] == null)
{
guid = System.Guid.NewGuid().ToString();
log.Debug("SetCurPageGuid注册了一个新的标识:" + guid);
}
else
guid = GetCurPageGuid();
}
else
{
guid = GetCurPageGuid();
}
ClientScript.RegisterHiddenField(HIDDEN_PAGE_GUID, guid);
return guid;
}
/// <summary>
/// 得到当前页面的唯一标识
/// </summary>
/// <returns></returns>
private string GetCurPageGuid()
{
string pageGuid = Request.Params[HIDDEN_PAGE_GUID] == null ? "none" : Request.Params[HIDDEN_PAGE_GUID].ToString();
log.Debug("执行GetCurPageGuid()后Page_GUID为:" + pageGuid);
return pageGuid;
}
}
需要刷新判断功能时新页面只需继承该类就可,通过引用属性IsPageRefreshed识别"为真表示刷新,假则是正常提交",将数据库的操作写在
if(!IsPageRefreshed)
{
数据库操作
}
即可,如果是刷新不会执行,代码中注释部分使用的是Session方式保存票证,因为session比较容易丢失且占内存,所以使用cookie,