CacheItem Class

Definition

Namespace:

System.Runtime.Caching

Assembly:

System.Runtime.Caching.dll

Package:

System.Runtime.Caching v10.0.0-preview.1.25080.5

Source:

CacheItem.cs

Represents an individual cache entry in the cache.

C#

public class CacheItem

Inheritance

Object

CacheItem

Examples

The following example shows how to use the CacheItem class to store the contents of a file as a cache entry.

C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Runtime.Caching;
using System.IO;

public partial class _Default : System.Web.UI.Page
{

    protected void Button1_Click(object sender, EventArgs e)
    {
        ObjectCache cache = MemoryCache.Default;

        CacheItem fileContents = cache.GetCacheItem("filecontents");

        if (fileContents == null)
        {
            CacheItemPolicy policy = new CacheItemPolicy();

            List<string> filePaths = new List<string>();
            string cachedFilePath = Server.MapPath("~") +
                "\\cacheText.txt";

            filePaths.Add(cachedFilePath);

            policy.ChangeMonitors.Add(new HostFileChangeMonitor(filePaths));

            // Fetch the file contents
            string fileData = File.ReadAllText(cachedFilePath);

            fileContents = new CacheItem("filecontents", fileData);

            cache.Set(fileContents, policy);
        }
        Label1.Text = (fileContents.Value as string);
    }
}

Remarks

The CacheItem class provides a logical representation of a cache entry, which can include regions by using the RegionName property. In the default ASP.NET cache implementation, a cache entry is a key/value pair.

Entries in the cache are not CacheItem instances. Instead, the cache provider can store cache entries in any internal format that is convenient. However, the cache API requires cache providers to be able to convert cache entries into CacheItem instances (and vice versa).

Custom cache implementations can inherit from the CacheItem class provide additional information about cache entries.

Notes to Inheritors

The ObjectCache class has methods that support adding, fetching, and updating cache data, and all these methods have overloads that support the CacheItem class. Therefore, a custom cache implementation can create an extended CacheItem class and use that extended class together with the existing ObjectCache API for cache entries.

Constructors

CacheItem(String, Object, String)	Initializes a new CacheItem instance using the specified key, value, and region of the cache entry.
CacheItem(String, Object)	Initializes a new CacheItem instance using the specified key and a value of the cache entry.
CacheItem(String)	Initializes a new CacheItem instance using the specified key of a cache entry.

Properties

Key	Gets or sets a unique identifier for a CacheItem instance.
RegionName	Gets or sets the name of a region in the cache that contains a CacheItem entry.
Value	Gets or sets the data for a CacheItem instance.

Applies to

See also

• ObjectCache