Telerik RadPersistenceManager 无法读取存储内容答案

【问题标题】：Telerik RadPersistenceManager Unable to read storage contentTelerik RadPersistenceManager 无法读取存储内容
【发布时间】：2015-05-24 15:36:06
【问题描述】：

我已将 RadPersistenceManager 与 asp.net 一起使用，并遵循以下指南：

http://demos.telerik.com/aspnet-ajax/persistence-framework/examples/custom-storage-provider/defaultcs.aspx.

但是当我在我的项目中实现它时，会出现以下异常：

标题：xxxx.aspx，xxxxxx 方法名：无法读取存储内容。找不到文件 'C:\inetpub\wwwroot\XXXX\App_Data\TelerikAspNetRadControlsPersistedState'。

例外：在 Telerik.Web.UI.PersistenceFramework.AppDataStorageProvider.LoadStateFromStorage（字符串键）在 Telerik.Web.UI.RadPersistenceManager.LoadState() 在 GraphicalUserInterface.JobBasket.LoadGridJobBasket()

【问题讨论】：

请发布产生此错误的代码。
与上述指南中的代码相同，只是 RadScriptManager 在母版页中。

标签： c# asp.net telerik telerik-grid

【解决方案1】：

这是默认的存储提供程序密钥。如果控件正在寻找它，那么您的自定义提供程序根本没有生效。

确保您拥有演示中的所有内容，主要是：

设置自定义存储提供程序的行：

protected void Page_Init(object sender, EventArgs e)
{
    RadPersistenceManager1.StorageProviderKey = CookieName;
    RadPersistenceManager1.StorageProvider = new CookieStorageProvider(CookieName);
}

以及自定义存储提供程序本身：

using System;
using System.Linq;
using System.Web;
using Telerik.Web.UI.PersistenceFramework;
using System.IO;
using System.IO.Compression;
using System.Text;

public class CookieStorageProvider : IStateStorageProvider
{
    private static readonly Encoding AsciiEncoding = System.Text.Encoding.ASCII;
    private static readonly int MaxCookieSize = 4000;
    private static readonly int LengthDataByteCount = sizeof(Int32);
    private string StorageKey { get; set; }

    #region IStateStorageProvider

    public CookieStorageProvider(string key)
    {
        StorageKey = key;
    }

    public void SaveStateToStorage(string key, string serializedState)
    {
        HttpCookie cookie = new HttpCookie(StorageKey);
        string settingsData = CompressString(serializedState);

        if (settingsData.Length > MaxCookieSize)
        {
            throw new ArgumentOutOfRangeException("Current settings exceed 4k in compressed form! Operation canceled!");
        }

        cookie.Value = settingsData;

        HttpContext.Current.Response.Cookies.Add(cookie);
    }

    public string LoadStateFromStorage(string key)
    {
        return DecompressString(HttpContext.Current.Request.Cookies[StorageKey].Value.ToString());
    }

    #endregion

    private string CompressString(string inputString)
    {
        byte[] outputBytes = null;
        byte[] inputBytes = AsciiEncoding.GetBytes(inputString);

        using (MemoryStream ms = new MemoryStream())
        {
            using (GZipStream zipStream = new GZipStream(ms, CompressionMode.Compress))
            {
                zipStream.Write(inputBytes, 0, inputBytes.Length);
            }
            outputBytes = ms.ToArray();
        }

        return Convert.ToBase64String(AddDataCount(outputBytes, inputBytes.Length));
    }

    private string DecompressString(string inputString)
    {
        string outputString = String.Empty;
        byte[] inputBytes = Convert.FromBase64String(inputString);
        Int32 lengthDataArray = BitConverter.ToInt32(inputBytes, inputBytes.Length - LengthDataByteCount);
        byte[] outputBytes = new byte[lengthDataArray];

        using (MemoryStream ms = new MemoryStream(RemoveDataCount(inputBytes)))
        {
            using (GZipStream zipStream = new GZipStream(ms, CompressionMode.Decompress))
            {
                zipStream.Read(outputBytes, 0, outputBytes.Length);
            }
            outputString = AsciiEncoding.GetString(outputBytes);
        }

        return outputString;
    }

    private byte[] AddDataCount(byte[] inputArray, Int32 length)
    {
        byte[] lengthDataArray = BitConverter.GetBytes(length);
        Array.Resize<byte>(ref inputArray, inputArray.Length + LengthDataByteCount);
        Array.Copy(lengthDataArray, 0, inputArray, inputArray.Length - LengthDataByteCount, LengthDataByteCount);
        return inputArray;
    }

    private byte[] RemoveDataCount(byte[] inputArray)
    {
        Array.Resize<byte>(ref inputArray, inputArray.Length - LengthDataByteCount);
        return inputArray;
    }
}

【讨论】：

【解决方案2】：

演示和我的示例之间的不同之处在于我需要在页面加载而不是加载按钮时加载持久性配置。所以有时CookieStorageProvider似乎没有在Page_Init中启动，所以我将它添加到page_load中。

【讨论】：