ObjectDataSource.SqlCacheDependency Propriété
Définition
Important
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Obtient ou définit une chaîne délimitée par des points-virgules qui indique les bases de données et les tables à utiliser pour la dépendance de cache Microsoft SQL Server.
public:
virtual property System::String ^ SqlCacheDependency { System::String ^ get(); void set(System::String ^ value); };public virtual string SqlCacheDependency { get; set; }member this.SqlCacheDependency : string with get, setPublic Overridable Property SqlCacheDependency As StringValeur de propriété
Chaîne qui indique les bases de données et les tables à utiliser pour la dépendance de cache SQL Server.
Exemples
Cette section contient deux exemples de code. Le premier exemple de code montre comment créer une dépendance de cache SQL Server et définir la SqlCacheDependency propriété d’un ObjectDataSource objet. Le deuxième exemple de code montre comment implémenter une méthode wrapper qui retourne un DataSet objet pour activer la mise en cache et le filtrage avec un ObjectDataSource objet.
L’exemple de code suivant montre comment créer une dépendance de cache SQL Server et définir la SqlCacheDependency propriété d’un ObjectDataSource contrôle. Dans cet exemple, la base de données est interrogée toutes les 120 secondes. Si les données de la table Northwind Traders Employees changent pendant cette période, toutes les données mises en cache par le ObjectDataSource contrôle et affichées par le GridView contrôle ont expiré et un nouvel ensemble de données est récupéré sur la demande suivante de la page.
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS" Assembly="Samples.AspNet.CS" %>
<%@ Page language="c#" %>
<!--
The page uses an example configuration that includes
connection strings and a defined SqlCacheDependecy.
<?xml version="1.0"?>
<configuration>
<connectionStrings>
<add name="MyNorthwind"
connectionString="Data Source="localhost";Integrated Security="SSPI";Initial Catalog="Northwind""
providerName="System.Data.SqlClient" />
</connectionStrings>
<system.web>
<cache>
<sqlCacheDependency enabled="true">
<databases>
<add
name="Northwind"
connectionStringName="MyNorthwind"
pollTime="120000" />
</databases>
</sqlCacheDependency>
</cache>
</system.web>
</configuration>
-->
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>ObjectDataSource - C# Example</title>
</head>
<body>
<form id="Form1" method="post" runat="server">
<asp:gridview
id="GridView1"
runat="server"
datasourceid="ObjectDataSource1" />
<asp:objectdatasource
id="ObjectDataSource1"
runat="server"
typename="Samples.AspNet.CS.EmployeeLogic"
selectmethod="GetAllEmployeesAsDataSet"
enablecaching="True"
cacheduration="300"
cacheexpirationpolicy="Absolute"
sqlcachedependency="Northwind:Employees" />
</form>
</body>
</html>
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.VB" Assembly="Samples.AspNet.VB" %>
<%@ Page language="vb" %>
<!--
The page uses an example configuration that includes
connection strings and a defined SqlCacheDependecy.
<?xml version="1.0"?>
<configuration>
<connectionStrings>
<add name="MyNorthwind"
connectionString="Data Source="localhost";Integrated Security="SSPI";Initial Catalog="Northwind""
providerName="System.Data.SqlClient" />
</connectionStrings>
<system.web>
<cache>
<sqlCacheDependency enabled="true">
<databases>
<add
name="Northwind"
connectionStringName="MyNorthwind"
pollTime="120000" />
</databases>
</sqlCacheDependency>
</cache>
</system.web>
</configuration>
-->
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>ObjectDataSource - VB Example</title>
</head>
<body>
<form id="Form1" method="post" runat="server">
<asp:gridview
id="GridView1"
runat="server"
datasourceid="ObjectDataSource1" />
<asp:objectdatasource
id="ObjectDataSource1"
runat="server"
typename="Samples.AspNet.VB.EmployeeLogic"
selectmethod="GetAllEmployeesAsDataSet"
enablecaching="True"
cacheduration="300"
cacheexpirationpolicy="Absolute"
sqlcachedependency="Northwind:Employees" />
</form>
</body>
</html>
L’exemple de code suivant montre comment implémenter une méthode wrapper qui retourne un DataSet objet pour activer la mise en cache et le filtrage avec un ObjectDataSource contrôle. Dans l’implémentation de base de la EmployeeLogic classe, la GetAllEmployees méthode retourne un ArrayList objet. Au lieu de refactoriser complètement l’objet pour travailler avec la ObjectDataSource page d’un Web Forms, une méthode wrapper nommée GetAllEmployeesAsDataSet est ajoutée qui retourne un jeu de NorthwindEmployee données en tant que DataSet.
namespace Samples.AspNet.CS {
using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Web.UI;
using System.Web.UI.WebControls;
//
// EmployeeLogic is a stateless business object that encapsulates
// the operations one can perform on a NorthwindEmployee object.
//
public class EmployeeLogic {
// Returns a collection of NorthwindEmployee objects.
public static ICollection GetAllEmployees () {
ArrayList al = new ArrayList();
ConnectionStringSettings cts = ConfigurationManager.ConnectionStrings["NorthwindConnection"];
SqlDataSource sds
= new SqlDataSource(cts.ConnectionString,
"SELECT EmployeeID FROM Employees");
try {
IEnumerable IDs = sds.Select(DataSourceSelectArguments.Empty);
// Iterate through the Enumeration and create a
// NorthwindEmployee object for each ID.
IEnumerator enumerator = IDs.GetEnumerator();
while (enumerator.MoveNext()) {
// The IEnumerable contains DataRowView objects.
DataRowView row = enumerator.Current as DataRowView;
string id = row["EmployeeID"].ToString();
NorthwindEmployee nwe = new NorthwindEmployee(id);
// Add the NorthwindEmployee object to the collection.
al.Add(nwe);
}
}
finally {
// If anything strange happens, clean up.
sds.Dispose();
}
return al;
}
//
// To support basic filtering, the employees cannot
// be returned as an array of objects, rather as a
// DataSet of the raw data values.
public static DataSet GetAllEmployeesAsDataSet () {
ICollection employees = GetAllEmployees();
DataSet ds = new DataSet("Table");
// Create the schema of the DataTable.
DataTable dt = new DataTable();
DataColumn dc;
dc = new DataColumn("FirstName", typeof(string)); dt.Columns.Add(dc);
dc = new DataColumn("LastName", typeof(string)); dt.Columns.Add(dc);
dc = new DataColumn("Title", typeof(string)); dt.Columns.Add(dc);
dc = new DataColumn("Courtesy", typeof(string)); dt.Columns.Add(dc);
dc = new DataColumn("Supervisor",typeof(Int32)); dt.Columns.Add(dc);
// Add rows to the DataTable.
IEnumerator emplEnum = employees.GetEnumerator();
DataRow row;
NorthwindEmployee ne;
while (emplEnum.MoveNext()) {
ne = emplEnum.Current as NorthwindEmployee;
row = dt.NewRow();
row["FirstName"] = ne.FirstName;
row["LastName"] = ne.LastName;
row["Title"] = ne.Title;
row["Courtesy"] = ne.Courtesy;
row["Supervisor"] = ne.Supervisor;
dt.Rows.Add(row);
}
// Add the complete DataTable to the DataSet.
ds.Tables.Add(dt);
return ds;
}
public static NorthwindEmployee GetEmployee(object anID) {
if (anID.Equals("-1") ||
anID.Equals(DBNull.Value) ) {
return new NorthwindEmployee();
}
else {
return new NorthwindEmployee(anID);
}
}
public static void UpdateEmployeeInfo(NorthwindEmployee ne) {
bool retval = ne.Save();
if (! retval) { throw new NorthwindDataException("UpdateEmployee failed."); }
}
public static void DeleteEmployee(NorthwindEmployee ne) {
bool retval = ne.Delete();
if (! retval) { throw new NorthwindDataException("DeleteEmployee failed."); }
}
}
public class NorthwindEmployee {
public NorthwindEmployee () {
ID = DBNull.Value;
lastName = "";
firstName = "";
title="";
titleOfCourtesy = "";
reportsTo = -1;
}
public NorthwindEmployee (object anID) {
this.ID = anID;
SqlConnection conn
= new SqlConnection (ConfigurationManager.ConnectionStrings["NorthwindConnection"].ConnectionString);
SqlCommand sc =
new SqlCommand(" SELECT FirstName,LastName,Title,TitleOfCourtesy,ReportsTo " +
" FROM Employees " +
" WHERE EmployeeID = @empId",
conn);
// Add the employee ID parameter and set its value.
sc.Parameters.Add(new SqlParameter("@empId",SqlDbType.Int)).Value = Int32.Parse(anID.ToString());
SqlDataReader sdr = null;
try {
conn.Open();
sdr = sc.ExecuteReader();
// Only loop once.
if (sdr != null && sdr.Read()) {
// The IEnumerable contains DataRowView objects.
this.firstName = sdr["FirstName"].ToString();
this.lastName = sdr["LastName"].ToString();
this.title = sdr["Title"].ToString();
this.titleOfCourtesy = sdr["TitleOfCourtesy"].ToString();
if (! sdr.IsDBNull(4)) {
this.reportsTo = sdr.GetInt32(4);
}
}
else {
throw new NorthwindDataException("Data not loaded for employee id.");
}
}
finally {
try {
if (sdr != null) sdr.Close();
conn.Close();
}
catch (SqlException) {
// Log an event in the Application Event Log.
throw;
}
}
}
private object ID;
public string EmpID {
get { return ID.ToString(); }
}
private string lastName;
public string LastName {
get { return lastName; }
set { lastName = value; }
}
private string firstName;
public string FirstName {
get { return firstName; }
set { firstName = value; }
}
public string FullName {
get { return FirstName + " " + LastName; }
}
private string title;
public String Title {
get { return title; }
set { title = value; }
}
private string titleOfCourtesy;
public string Courtesy {
get { return titleOfCourtesy; }
set { titleOfCourtesy = value; }
}
private int reportsTo;
public int Supervisor {
get { return reportsTo; }
set { reportsTo = value; }
}
public bool Save () {
// Implement persistence logic.
return true;
}
public bool Delete () {
// Implement delete logic.
return true;
}
}
internal class NorthwindDataException: Exception {
public NorthwindDataException(string msg) : base (msg) { }
}
}
Imports System.Collections
Imports System.Configuration
Imports System.Data
Imports System.Data.SqlClient
Imports System.Web.UI
Imports System.Web.UI.WebControls
Namespace Samples.AspNet.VB
' EmployeeLogic is a stateless business object that encapsulates
' the operations one can perform on a NorthwindEmployee object.
'
Public Class EmployeeLogic
' Returns a collection of NorthwindEmployee objects.
Public Shared Function GetAllEmployees() As ICollection
Dim al As New ArrayList()
Dim cts As ConnectionStringSettings = ConfigurationManager.ConnectionStrings("NorthwindConnection")
Dim sds As New SqlDataSource(cts.ConnectionString, "SELECT EmployeeID FROM Employees")
Try
Dim IDs As IEnumerable = sds.Select(DataSourceSelectArguments.Empty)
' Iterate through the Enumeration and create a
' NorthwindEmployee object for each ID.
Dim enumerator As IEnumerator = IDs.GetEnumerator()
While enumerator.MoveNext()
' The IEnumerable contains DataRowView objects.
Dim row As DataRowView = CType(enumerator.Current,DataRowView)
Dim id As String = row("EmployeeID").ToString()
Dim nwe As New NorthwindEmployee(id)
' Add the NorthwindEmployee object to the collection.
al.Add(nwe)
End While
Finally
' If anything strange happens, clean up.
sds.Dispose()
End Try
Return al
End Function 'GetAllEmployees
' To support basic filtering, the employees cannot
' be returned as an array of objects, rather as a
' DataSet of the raw data values.
Public Shared Function GetAllEmployeesAsDataSet() As DataSet
Dim employees As ICollection = GetAllEmployees()
Dim ds As New DataSet("Table")
' Create the schema of the DataTable.
Dim dt As New DataTable()
Dim dc As DataColumn
dc = New DataColumn("FirstName", GetType(String))
dt.Columns.Add(dc)
dc = New DataColumn("LastName", GetType(String))
dt.Columns.Add(dc)
dc = New DataColumn("Title", GetType(String))
dt.Columns.Add(dc)
dc = New DataColumn("Courtesy", GetType(String))
dt.Columns.Add(dc)
dc = New DataColumn("Supervisor", GetType(Int32))
dt.Columns.Add(dc)
' Add rows to the DataTable.
Dim emplEnum As IEnumerator = employees.GetEnumerator()
Dim row As DataRow
Dim ne As NorthwindEmployee
While emplEnum.MoveNext()
ne = CType(emplEnum.Current, NorthwindEmployee)
row = dt.NewRow()
row("FirstName") = ne.FirstName
row("LastName") = ne.LastName
row("Title") = ne.Title
row("Courtesy") = ne.Courtesy
row("Supervisor") = ne.Supervisor
dt.Rows.Add(row)
End While
' Add the complete DataTable to the DataSet.
ds.Tables.Add(dt)
Return ds
End Function 'GetAllEmployeesAsDataSet
Public Shared Function GetEmployee(anID As Object) As NorthwindEmployee
If anID.Equals("-1") OrElse anID.Equals(DBNull.Value) Then
Return New NorthwindEmployee()
Else
Return New NorthwindEmployee(anID)
End If
End Function 'GetEmployee
Public Shared Sub UpdateEmployeeInfo(ne As NorthwindEmployee)
Dim retval As Boolean = ne.Save()
If Not retval Then
Throw New NorthwindDataException("UpdateEmployee failed.")
End If
End Sub
Public Shared Sub DeleteEmployee(ne As NorthwindEmployee)
Dim retval As Boolean = ne.Delete()
If Not retval Then
Throw New NorthwindDataException("DeleteEmployee failed.")
End If
End Sub
End Class
Public Class NorthwindEmployee
Public Sub New()
ID = DBNull.Value
aLastName = ""
aFirstName = ""
aTitle = ""
titleOfCourtesy = ""
reportsTo = - 1
End Sub
Public Sub New(anID As Object)
Me.ID = anID
Dim cts As ConnectionStringSettings = ConfigurationManager.ConnectionStrings("NorthwindConnection")
Dim conn As New SqlConnection(cts.ConnectionString)
Dim sc As New SqlCommand(" SELECT FirstName,LastName,Title,TitleOfCourtesy,ReportsTo " & _
" FROM Employees " & _
" WHERE EmployeeID = @empId", conn)
' Add the employee ID parameter and set its value.
sc.Parameters.Add(New SqlParameter("@empId", SqlDbType.Int)).Value = Int32.Parse(anID.ToString())
Dim sdr As SqlDataReader = Nothing
Try
conn.Open()
sdr = sc.ExecuteReader()
' Only loop once.
If Not (sdr Is Nothing) AndAlso sdr.Read() Then
' The IEnumerable contains DataRowView objects.
Me.aFirstName = sdr("FirstName").ToString()
Me.aLastName = sdr("LastName").ToString()
Me.aTitle = sdr("Title").ToString()
Me.titleOfCourtesy = sdr("TitleOfCourtesy").ToString()
If Not sdr.IsDBNull(4) Then
Me.reportsTo = sdr.GetInt32(4)
End If
Else
Throw New NorthwindDataException("Data not loaded for employee id.")
End If
Finally
Try
If Not (sdr Is Nothing) Then
sdr.Close()
End If
conn.Close()
Catch se As SqlException
' Log an event in the Application Event Log.
Throw
End Try
End Try
End Sub
Private ID As Object
Public ReadOnly Property EmpID() As String
Get
Return ID.ToString()
End Get
End Property
Private aLastName As String
Public Property LastName() As String
Get
Return aLastName
End Get
Set
aLastName = value
End Set
End Property
Private aFirstName As String
Public Property FirstName() As String
Get
Return aFirstName
End Get
Set
aFirstName = value
End Set
End Property
Public ReadOnly Property FullName() As String
Get
Return FirstName & " " & LastName
End Get
End Property
Private aTitle As String
Public Property Title() As String
Get
Return aTitle
End Get
Set
aTitle = value
End Set
End Property
Private titleOfCourtesy As String
Public Property Courtesy() As String
Get
Return titleOfCourtesy
End Get
Set
titleOfCourtesy = value
End Set
End Property
Private reportsTo As Integer
Public Property Supervisor() As Integer
Get
Return reportsTo
End Get
Set
reportsTo = value
End Set
End Property
Public Function Save() As Boolean
' Implement persistence logic.
Return True
End Function 'Save
Public Function Delete() As Boolean
' Implement delete logic.
Return True
End Function 'Delete
End Class
Friend Class NorthwindDataException
Inherits Exception
Public Sub New(msg As String)
MyBase.New(msg)
End Sub
End Class
End Namespace
Remarques
Le ObjectDataSource contrôle prend en charge une stratégie d’expiration facultative basée sur l’objet SqlCacheDependency du cache de données (le service doit être configuré pour le serveur de base de données).
SQL Server prend en charge deux mécanismes pour l’invalidation du cache : interrogation et notification. Chaque mécanisme a une syntaxe différente pour l’objet SqlCacheDependency .
Le ObjectDataSource seul sondage prend en charge l’interrogation. La SqlCacheDependency chaîne est utilisée pour créer un SqlDependency objet transmis au DbCommand constructeur avant l’exécution de la Select méthode. La SqlCacheDependency chaîne identifie les bases de données et les tables selon le même format utilisé par la @ Page directive, où la première partie de la chaîne est une chaîne de connexion à une base de données SQL Server, suivie d’un délimiteur deux-points, et enfin le nom de la table de base de données (par exemple"connectionstring1:table1"). Si la SqlCacheDependency propriété dépend de plusieurs tables, les paires chaîne de connexion et nom de table sont séparées par des points-virgules (par exemple). "connectionstring1:table1";connectionstring2:table2"
Pour prendre en charge la notification, vous devez écrire la logique de cache dans l’implémentation de votre SelectMethod propriété et gérer la construction de l’objet SqlCacheDependency dans votre code.