SqlCacheDependency

SqlCacheDependency

web页面代码片段：

web页面代码

String connectionString = " Data Source=localhost;Initial Catalog=BalloonShop;Integrated Security=True " ;
DataTable dt = (DataTable)HttpContext.Current.Cache[ " Customer_test " ];
if (dt == null )
{
using (SqlConnection conn = new SqlConnection(connectionString))
{
String sqlStr = " SELECT dbo.Product.ProductID, Name, col_name FROM " +
" dbo.Product inner join dbo.ProductCategory on " +
" dbo.Product.ProductID = dbo.ProductCategory.ProductID inner join " +
" dbo.tb_category on dbo.ProductCategory.CategoryID = dbo.tb_category.col_id " ;
conn.Open();
SqlCommand command = new SqlCommand();
command.Connection = conn;
command.CommandText = sqlStr;
// DataTableCache.Dependency = new SqlCacheDependency(command);
SqlCacheDependency dependency = new SqlCacheDependency(command)；
　　　　　　　　　SqlDataAdapter adapter = new SqlDataAdapter(command);
DataSet ds = new DataSet();
adapter.Fill(ds, " Customers " );
dt = ds.Tables[ 0 ];
// command.Connection.Close();
DataTableCache.AddCache( "Customer_test" , dt, command);//缓存通知失效 不起作用
　　　　 DataTableCache.AddCache("Customer_test", dt, dependency );// 成功
// HttpContext.Current.Cache.Insert("Customer_test", dt, dependency);

}
}

gvwCustomers.DataSource = dt;
gvwCustomers.DataBind();

DataTableCahche的代码片段：

DataTableCache代码

public class DataTableCache
{
private DataTableCache(){ }
private static SqlCacheDependency dependency = null ;

public static SqlCacheDependency Dependency {
get { return dependency; }
set { dependency = value; }
}
public static void AddCache(String key, DataTable dt,SqlCommand command) {
dependency = new SqlCacheDependency(command);
HttpContext.Current.Cache.Insert(key, dt, dependency);
}
public static void AddCache(String key, DataTable dt, SqlCacheDependency dependency) {
HttpContext.Current.Cache.Insert(key, dt, dependency);
}
public static void AddCache(String key, DataTable dt) {
HttpRuntime.Cache.Insert(key,dt, dependency);
}
}
当我使用上面红色的部分插入cache的时候，我改变数据库中的数据时，界面上的数据却不会变化，通知失效机制不能成功运行，
当我使用蓝色的部分插入cache的时候， 我改变数据库中的数据时，界面上的数据能发生变化，通知失效机制能成功运行，我很困惑，这到底是什么原因？

小丁
菜鸟二级
专家分-301

提问于2010-01-19 11:57

进入新版

所有回答(2)

0 0

这个有问题



 private static SqlCacheDependency dependency = null;

    public static SqlCacheDependency Dependency {
        get { return dependency; }
        set { dependency = value; }
    }
    public static void AddCache(String key, DataTable dt,SqlCommand command) {
         dependency = new SqlCacheDependency(command);
         HttpContext.Current.Cache.Insert(key, dt, dependency);
    }

应该是你这边全局static有点问题，更改成静态单件构造函

你更改成试试：




 public static void AddCache(String key, DataTable dt,SqlCommand command) {       
SqlCacheDependency  _dependency = new SqlCacheDependency(command);
         HttpContext.Current.Cache.Insert(key, dt, _dependency);
    }

persialee
老鸟四级
专家分-3217

回答于2010-01-19 15:47

这个我试过，好像也不行，
还有就是问题出在command上，在command执行以后，比如执行以下语句之后：
command.ExecuteReader();
或
SqlDataAdapter adapter = new SqlDataAdapter(command);
在把command赋给SqlCacheDependency时就会不起作用，
而在command执行之前赋给SqlCacheDependency就可以，
但我不太清楚这里边的运行机制

小丁的博客
菜鸟二级
专家分-301

评论于2010-01-19 16:59

1 0

看看这里
http://www.dotnetcurry.com/ShowArticle.aspx?ID=263&AspxAutoDetectCookieSupport=1

的确需要在 cmd.ExecuteNonQuery();之前执行

  SqlCacheDependency dependency = new SqlCacheDependency(cmd);