WebPart.PartCacheWrite Method

Stores the specified value of the specified type of storage in the Web Part cache.

Namespace:  Microsoft.SharePoint.WebPartPages
Assembly:  Microsoft.SharePoint (in Microsoft.SharePoint.dll)
Available in Sandboxed Solutions: No

Syntax

'Declaration
Protected Sub PartCacheWrite ( _
    storage As Storage, _
    key As String, _
    value As Object, _
    timeout As TimeSpan _
)
'Usage
Dim storage As Storage
Dim key As String
Dim value As Object
Dim timeout As TimeSpan

Me.PartCacheWrite(storage, key, value, _
    timeout)

protected void PartCacheWrite(
    Storage storage,
    string key,
    Object value,
    TimeSpan timeout
)

Parameters

• storage
  Type: Microsoft.SharePoint.WebPartPages.Storage

  A Storage value that specifies the type of storage in the Web Part cache where a value is stored. Possible values are Personal and Shared. Specifying None stores nothing.

• key
  Type: System.String

  The name to be used as the key for the value to be stored in the Web Part cache.

• value
  Type: System.Object

  A System.Object that contains the value to be stored.

• timeout
  Type: System.TimeSpan

  A System.TimeSpan that specifies the period during which PartCacheWrite attempts to write a value.

Remarks

If the CacheType is CacheObject, any object can be stored in the cache. If the CacheType is Database, then the object must be marked as serializable (System.SerializableAttribute).

Examples

The following code example shows a Web Part that caches and displays the time when it is first rendered, and provides a button to refresh the Web Part cache with the current time.

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") + "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;"))
         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")+ "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;");
            this.RenderChildren(output);
        }

        private string fetchData()
        {
            return DateTime.Now.ToLongTimeString();
        }
    }
}
               

See Also

Reference

WebPart Class

WebPart Members

Microsoft.SharePoint.WebPartPages Namespace