asp.net mvc---session cache (10)

1、记录用户访问人数

  首先定义一个用户访问类型 

 

public enum VisitorTypes {
  UnknownVisitor = 0,
  KnownVisitor = 1
}

 

   然后建立一个类

public class SiteVisitors {
  private static SiteVisitors instance = new SiteVisitors();
  private SiteVisitors() { }
  public int UnknownVisitorCount { get; private set; }
  public int KnownVisitorCount { get; private set; }
  public static SiteVisitors Instance {
    get {
          return instance;
        }
  }

  //user arrives

  public void UnknownVisitorArrived() {
     SessionWrapper.SetUnknownType();
     UnknownVisitorCount++;
  }
  //known user arrives
  public void KnownVisitorArrives() {
     SessionWrapper.SetKnownType();
     KnownVisitorCount++;
  }
  //user logs in
  public void UnknownVisitorLoggedOn() {
     SessionWrapper.SetKnownType();
     UnknownVisitorCount--;
     KnownVisitorCount++;
  }
  //user logs out
  public void KnownVisitorLoggedOut() {
     SessionWrapper.SetUnknownType();
     UnknownVisitorCount++;
     KnownVisitorCount--;
  }
  //user session expires
  public void VisitorLeft() {
    if (SessionWrapper.GetType() ==
       VisitorTypes.KnownVisitor)
       KnownVisitorLeft();
    else
      UnknownVisitorLeft();
  }

 

} 

建立一个静态类 

public static class SessionWrapper {
  private const string c_visitorType = "VisitorType";
  public static void SetUnknownType() {
    HttpContext.Current.Session.Add(c_visitorType, 
      VisitorTypes.UnknownVisitor);
  }
  public static void SetKnownType() {
    HttpContext.Current.Session.Add(c_visitorType, 
       VisitorTypes.KnownVisitor);
  }
  public static new VisitorTypes GetType() {
    VisitorTypes result = VisitorTypes.UnknownVisitor;
    if (HttpContext.Current.Session[c_visitorType] != null)
      result = (VisitorTypes)HttpContext.Current.Session 
        [c_visitorType];
    return result;
  }} 

使用：

protected void Session_Start() {

  if(Request.IsAuthenticated)
     SiteVisitors.Instance.KnownVisitorArrives();
  else
     SiteVisitors.Instance.UnknownVisitorArrived();
}
protected void Session_End() {
     SiteVisitors.Instance.VisitorLeft();
}

 前台调用

<div id="logindisplay">

  <% Html.RenderPartial("LogOnUserControl"); %><br />
  Known visitor count: <%: 
    StateExamples.Models.SiteVisitors.Instance
      .KnownVisitorCount %> - Unknown visitor count: 
    <%: 
    StateExamples.Models.SiteVisitors.Instance.UnknownVisitorCount 
     %>
</div> 

 2、使用sessionwap记录访问信息

    public static class SessionWrapper {

  private const string c_account = "Account";
  public static Account Account {
    get { return GetObjectFromSession(c_account) as Account; }
    set {
      if (value == null)
         ClearItemFromSession(c_account);
      else
         SetItemInSession(value, c_account);
    }
  }
  private static string GetStringFromSession(string key) {
     return GetObjectFromSession(key).ToString();
  }
  private static int GetIntFromSession(string key) {
     return (int)GetObjectFromSession(key);
  }
  private static object GetObjectFromSession(string key) {
    return HttpContext.Current.Session[key];
  }

 

 private static void SetItemInSession(object item, string key) { 

 HttpContext.Current.Session.Add(key, item);

  }

  private static void ClearItemFromSession(string key) {

     HttpContext.Current.Session.Remove(key);

  }

} 

 

 

 在登录上使用 

    SessionWrapper.Account = new AccountService() .GetAccountByUsername(userName);

在前台使用 ：

<div id="logindisplay">
  <% Html.RenderPartial("LogOnUserControl"); %><br />
  <%= StateExamples.Models.SessionWrapper.Account != null  
    ? "Welcome " +  
    StateExamples.Models.SessionWrapper.Account.Username + " 
   from session wrapper!"  : "" %>

</div>  

 3、使用cache

   public class CacheWrapper

public class CacheWrapper {
  private List<object> GetCacheItems(string[] keys) {
   IDictionaryEnumerator theCache = 
      HttpContext.Current.Cache.GetEnumerator();
   List<object> results = new List<object>();
   while (theCache.MoveNext()) {
     if (keys.Contains(theCache.Key))
        results.Add(theCache.Value);
   }
    return results;
  }

  private object GetCachItem(string key) { 

if (HttpContext.Current.Cache[key] != null)
      return HttpContext.Current.Cache[key];
    return null;
  }
  private void AddCacheItems(Dictionary<string, object> items) {
    foreach (KeyValuePair<string, object> item in items) {
       AddCacheItem(item.Key, item.Value);
    }
  }
  private void AddCacheItem(string key, object item) {
   HttpContext.Current.Cache.Add(key, item, null, //dependencies 
      DateTime.MaxValue, //absolute expiration 
      new TimeSpan(0, 1, 0, 0), //sliding expiration 
      CacheItemPriority.Default, //priority 
      null); //callback
  }

 public void PutProducts(List<Product> products) {

    Dictionary<string, object> itemsToCache = new 

       Dictionary<string, object>();

    foreach (Product product in products) {

       itemsToCache.Add(product.Name, product);

    }

    AddCacheItems(itemsToCache);

  }

  public List<Product> GetProducts(string[] productNames) {

     List<Product> results = new List<Product>();

     List<object> cacheItems = GetCacheItems(productNames);

     foreach (object cacheItem in cacheItems) {

        results.Add(cacheItem as Product);

     } 

 return results.OrderBy(p => p.Name).ToList();

  } 

 把产品预装

    private void PreLoadProductCatalog() {

  List<Product> products = new ProductService().GetProducts();
  new CacheWrapper().PutProducts(products);

}

 

然后如何获取

 List<Product> products = new CacheWrapper().GetProducts(new[] {
     "Name1", "Name5", "Name98", "Name39", "Name88", "Name34"
  });

 return View(products);  

 

4、使用页面缓存

   在action 上加

    [OutputCache(Duration = (60 * 60), VaryByParam = "none")]  

 5、