WebPart.PartCacheRead-Methode
Liest und gibt einen Wert aus der angegebenen Position in den angegebenen Typ des Speichers im Cache-Webpart.
Namespace: Microsoft.SharePoint.WebPartPages
Assembly: Microsoft.SharePoint (in Microsoft.SharePoint.dll)
Syntax
'Declaration
Protected Function PartCacheRead ( _
storage As Storage, _
key As String _
) As Object
'Usage
Dim storage As Storage
Dim key As String
Dim returnValue As Object
returnValue = Me.PartCacheRead(storage, _
key)
protected Object PartCacheRead(
Storage storage,
string key
)
Parameter
storage
Typ: Microsoft.SharePoint.WebPartPages.StorageEin Storage -Wert, der in der Webpartcache Speichertyp angibt, in dem ein Wert gelesen wird. Mögliche Werte sind Personal und Shared. Angeben von None gibt ein Nullverweis (Nothing in Visual Basic)zurück.
key
Typ: System.StringDer Name des Werts, der aus dem Cache Webpart gelesen werden.
Rückgabewert
Typ: System.Object
Ein object , der den Wert zurückgibt, der gelesen wird.
Beispiele
Das folgende Codebeispiel zeigt ein Webpart, das zwischengespeichert und die Uhrzeit, wann es wird zum ersten Mal gerendert und bietet eine Schaltfläche zum Aktualisieren des Caches-Webpart mit der aktuellen Zeit, anzeigt.
Imports System
Imports System.ComponentModel
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Xml.Serialization
Imports Microsoft.SharePoint
Imports Microsoft.SharePoint.Utilities
Imports Microsoft.SharePoint.WebPartPages
Namespace WebPartLibrary1
<DefaultProperty("Text"), _
ToolboxData("<{0}:CacheSample runat=server></{0}:CacheSample>"), _
XmlRoot([Namespace] := "WebPartLibrary1")>
Public Class CacheSample
Inherits Microsoft.SharePoint.WebPartPages.WebPart
Private refreshButton As Button
Public Sub New()
AddHandler Me.PreRender, AddressOf UpdateCache
End Sub
Protected Overrides Sub CreateChildControls()
refreshButton = New Button()
refreshButton.Text = "Refresh Cache"
AddHandler refreshButton.Click, AddressOf refreshButton_click
Me.Controls.Add(refreshButton)
End Sub
Public Sub UpdateCache(o As Object, e As System.EventArgs)
If Me.PartCacheRead(Storage.Shared, "cacheKey") Is Nothing Then
Me.PartCacheWrite(Storage.Shared, "cacheKey", fetchData(), TimeSpan.FromSeconds(10))
End If
End Sub
Private Sub refreshButton_click(o As Object, e As System.EventArgs)
Me.PartCacheInvalidate(Storage.Shared, "cacheKey")
End Sub
Protected Overrides Sub RenderWebPart(output As HtmlTextWriter)
output.Write("Cache Value: ")
output.Write((PartCacheRead(Storage.Shared, "cacheKey") + " "))
Me.RenderChildren(output)
End Sub
Private Function fetchData() As String
Return DateTime.Now.ToLongTimeString()
End Function
End Class
End Namespace
using System;
using System.ComponentModel;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Xml.Serialization;
using Microsoft.SharePoint;
using Microsoft.SharePoint.Utilities;
using Microsoft.SharePoint.WebPartPages;
namespace WebPartLibrary1
{
/// <summary>
/// Summary description for CacheSample.
/// </summary>
[DefaultProperty("Text"),
ToolboxData("<{0}:CacheSample runat=server></{0}:CacheSample>"),
XmlRoot(Namespace="WebPartLibrary1")]
public class CacheSample : Microsoft.SharePoint.WebPartPages.WebPart
{
Button refreshButton;
public CacheSample()
{
this.PreRender+=new EventHandler(UpdateCache);
}
protected override void CreateChildControls()
{
refreshButton = new Button();
refreshButton.Text="Refresh Cache";
refreshButton.Click+=new EventHandler(refreshButton_click);
this.Controls.Add(refreshButton);
}
public void UpdateCache(object o, System.EventArgs e)
{
if(this.PartCacheRead(Storage.Shared,"cacheKey") == null)
{
this.PartCacheWrite(Storage.Shared,"cacheKey", fetchData(), TimeSpan.FromSeconds(10));
}
}
private void refreshButton_click(object o, System.EventArgs e)
{
this.PartCacheInvalidate(Storage.Shared, "cacheKey");
}
protected override void RenderWebPart(HtmlTextWriter output)
{
output.Write("Cache Value: ");
output.Write(PartCacheRead(Storage.Shared,"cacheKey")+ " ");
this.RenderChildren(output);
}
private string fetchData()
{
return DateTime.Now.ToLongTimeString();
}
}
}