<%@ Page Language="C#" MasterPageFile="~/DefaultMaster.master" AutoEventWireup="true" CodeFile="CustomCaching.aspx.cs" Inherits="CustomCaching" Title="Custom Caching" %>

 

<%@ Register Assembly="ExtendedObjectDataSource" Namespace="Manu.Web.UI.WebControls" TagPrefix="manu" %>

 

<asp:Content ID="Content1" ContentPlaceHolderID="Content" Runat="Server">

    <h1>Custom Caching</h1>

 

 

    <asp:GridView ID="GridView1" runat="server" AllowPaging="True" AllowSorting="True"

        AutoGenerateColumns="False" CssClass="gridview" BackColor="#335789"

        BorderColor="#133769" BorderStyle="Solid" BorderWidth="1px"

        DataSourceID="ObjectDataSource1" PageSize="4" DataKeyNames="Id">

        <Columns>

            <asp:BoundField DataField="Id" HeaderText="Id" SortExpression="Id" />

            <asp:BoundField DataField="Name" HeaderText="Name" SortExpression="Name" />

            <asp:BoundField DataField="Description" HeaderText="Description" 
            SortExpression="Description" />

            <asp:BoundField DataField="Price" HeaderText="Price" SortExpression="Price" />

        </Columns>

        <RowStyle BackColor="White" ForeColor="#436799" />

        <HeaderStyle ForeColor="White" />

        <PagerStyle ForeColor="White" />

    </asp:GridView>

    <manu:MyCustomObjectDataSource ID="ObjectDataSource1" runat="server"
    OldValuesParameterFormatString="original_{0}" SelectMethod="LoadAll"
    TypeName="ProductsDAL" EnableCaching="True">

    </manu:MyCustomObjectDataSource>

</asp:Content>

using System;

using Manu.Web.UI.WebControls;

using Manu.Web.UI.WebControls.Caching;

 

namespace Samples

{

    /// <summary>A custom data source that caches information in the session.</summary>

    public class MyCustomObjectDataSource : ExtendedObjectDataSource

    {

        public MyCustomObjectDataSource()

        {

        }

 

        protected override IDataSourceCache CreateCache()

        {

            return new SessionCache(View);

        }

    }

}

using System;

using System.Collections.Specialized;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

using Manu.Web.UI.WebControls;

using Manu.Web.UI.WebControls.Caching;

 

/// <summary>A cache that saves the data in the session</summary>

public class SessionCache : BaseCache

{

    public SessionCache(CompatObjectDataSourceView view) : base(view)

    {

    }

 

    /// <summary>Gets the cached data.</summary>

    public override CachedResult GetData(DataSourceSelectArguments arguments, string 
                                       filterExpression, IOrderedDictionary allParameters)

    {

        // if the view supports custom paging, error

        if (View.EnablePaging) {

            throw new NotSupportedException(View.Owner.ID + ": Caching not supported with
                                                               paging");

        }

 

        // if the view supports custom sorting, error

        if (!String.IsNullOrEmpty(arguments.SortExpression) && 
           (View.SortParameterName.Length > 0)) {

            throw new NotSupportedException(View.Owner.ID + ": Caching not supported with
                                                               custom sorting");

        }

 

        // if the view supports custom filtering, error

        if(!String.IsNullOrEmpty(filterExpression)&&(View.FilterParameterName.Length>0)){

            throw new NotSupportedException(View.Owner.ID + ": Caching not supported with
                                                                custom filtering");

        }

 

        // gets the select parameters

        IOrderedDictionary parameters = CopyDictionary(View.SelectParameters.GetValues
                                                           (View.Context, View.Owner));

 

        // generate a key based on the select parameters

        string cacheKey = GenerateBaseCacheKey(parameters).ToString();

        return HttpContext.Current.Session[cacheKey] as CachedResult;

    }

 

    // saves data to the cache

    public override void SaveData(CachedResult data, DataSourceSelectArguments arguments,
                                string filterExpression, IOrderedDictionary selectParams)

    {

        // gets the select parameters

        IOrderedDictionary parameters = CopyDictionary(View.SelectParameters.GetValues
                                                        (View.Context, View.Owner));

 

        // generate a key to save the data to the cache

        string cacheKey = GenerateBaseCacheKey(parameters).ToString();

        if (HttpContext.Current.Session[cacheKey] == null) {

            HttpContext.Current.Session[cacheKey] = data;

        }

    }

 

    // invalidates the data stored in the cache

    public override void InvalidateData()

    {

        // gets the select parameters

        IOrderedDictionary parameters = CopyDictionary(View.SelectParameters.GetValues
                                                         (View.Context, View.Owner));

 

        // remove the base key to remove dependent entries

        string cacheKey = GenerateBaseCacheKey(parameters).ToString();

        HttpContext.Current.Session.Remove(cacheKey);

    }

}