穩紮穩打Silverlight(16) - 2.0資料之獨立存儲(Isolated Storage)

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穩紮穩打Silverlight(16) - 2.0資料之獨立存儲(Isolated Storage)

介紹

Silverlight 2.0 資料的獨立存儲(Isolated Storage)：

    IsolatedStorageFile - 操作 獨立存儲 的類

        IsolatedStorageFile.GetUserStoreForSite() - 按站點擷取使用者的獨立存儲

        IsolatedStorageFile.GetUserStoreForApplication() - 按應用程式擷取使用者的獨立存儲

    IsolatedStorageSettings - 在獨立存儲中儲存的 key-value 字典表

        IsolatedStorageSettings.SiteSettings - 按站點儲存的 key-value 字典表

        IsolatedStorageSettings.ApplicationSettings - 按應用程式儲存的 key-value 字典表

線上DEMO

示例

IsolatedStorage.xaml

&lt;UserControl x:Class="Silverlight20.Data.IsolatedStorage" 

        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"    

        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"&gt; 

        &lt;StackPanel HorizontalAlignment="Left"&gt; 

                &lt;TextBox x:Name="txtMsg" Margin="5" /&gt; 

                &lt;TextBox x:Name="txtMsg2" Margin="5" /&gt; 

                &lt;Button x:Name="increase" Content="增加配額" Click="increase_Click" Margin="5" /&gt; 

        &lt;/StackPanel&gt; 

&lt;/UserControl&gt;

IsolatedStorage.xaml.cs

using System; 

using System.Collections.Generic; 

using System.Linq; 

using System.Net; 

using System.Windows; 

using System.Windows.Controls; 

using System.Windows.Documents; 

using System.Windows.Input; 

using System.Windows.Media; 

using System.Windows.Media.Animation; 

using System.Windows.Shapes; 

using System.IO.IsolatedStorage; 

using System.IO; 

namespace Silverlight20.Data 

{ 

        public partial class IsolatedStorage : UserControl 

        { 

                public IsolatedStorage() 

                { 

                        InitializeComponent(); 

                        // 示範 IsolatedStorageFile 

                        Demo(); 

                        // 示範 IsolatedStorageSettings 

                        Demo2(); 

                } 

                /// &lt;summary&gt; 

                /// 示範 IsolatedStorageFile 

                /// &lt;/summary&gt; 

                void Demo() 

                        // Isolated Storage - 獨立存儲。一個虛拟檔案系統 

                        // IsolatedStorageFile - 操作 獨立存儲 的類 

                        //         IsolatedStorageFile.GetUserStoreForSite() - 按站點擷取使用者的獨立存儲 

                        //         IsolatedStorageFile.GetUserStoreForApplication() - 按應用程式擷取使用者的獨立存儲 

                        // using (IsolatedStorageFile isf = IsolatedStorageFile.GetUserStoreForSite()) 

                        using (IsolatedStorageFile isf = IsolatedStorageFile.GetUserStoreForApplication()) 

                        { 

                                // DirectoryExists(path) - 指定的路徑是否存在 

                                // CreateDirectory(path) - 建立指定的路徑 

                                // FileExists(path) - 指定的檔案是否存在 

                                // CreateFile(path) - 建立指定的檔案 

                                // GetDirectoryNames() - 擷取根目錄下的目錄名數組 

                                // GetFileNames()() - 擷取根目錄下的檔案名數組 

                                // GetDirectoryNames(path) - 擷取指定目錄下的目錄名數組 

                                // GetFileNames(path) - 擷取指定目錄下的檔案名數組 

                                // OpenFile() - 打開指定的檔案。具體參數參看文檔 

                                // DeleteFile(path) - 删除指定的檔案 

                                // DeleteDirectory(path) - 删除指定的目錄（要求目錄存在，且目錄内無内容） 

                                // Remove() - 關閉 IsolatedStorageFile 對象并移除獨立存儲内的全部内容 

                                // 在根目錄下建立指定的目錄 

                                if (!isf.DirectoryExists("Directory01")) 

                                        isf.CreateDirectory("Directory01"); 

                                if (!isf.DirectoryExists("Directory02")) 

                                        isf.CreateDirectory("Directory02"); 

                                // 建立指定的子目錄 

                                string subDirectory01 = System.IO.Path.Combine("Directory01", "SubDirectory01"); 

                                string subDirectory02 = System.IO.Path.Combine("Directory01", "SubDirectory02"); 

                                if (!isf.DirectoryExists(subDirectory01)) 

                                        isf.CreateDirectory(subDirectory01); 

                                if (!isf.DirectoryExists(subDirectory02)) 

                                        isf.CreateDirectory(subDirectory02); 

                                // 根目錄下建立指定的檔案 

                                if (!isf.FileExists("RootFile.txt")) 

                                { 

                                        IsolatedStorageFileStream isfs = isf.CreateFile("RootFile01.txt"); 

                                        isfs.Close(); 

                                } 

                                // 在指定的目錄下建立指定的檔案 

                                string file01 = System.IO.Path.Combine(subDirectory01, "File01.txt"); 

                                string file02 = System.IO.Path.Combine(subDirectory01, "File02.txt"); 

                                string file03 = System.IO.Path.Combine(subDirectory01, "File03.xml"); 

                                if (!isf.FileExists(file01)) 

                                        // IsolatedStorageFileStream - 獨立存儲内的檔案流。繼承自 FileStream 

                                        IsolatedStorageFileStream isfs = isf.CreateFile(file01); 

                                if (!isf.FileExists(file02)) 

                                        IsolatedStorageFileStream isfs = isf.CreateFile(file02); 

                                if (!isf.FileExists(file03)) 

                                        IsolatedStorageFileStream isfs = isf.CreateFile(file03); 

                                txtMsg.Text += "根目錄下的目錄清單：\r\n"; 

                                // 擷取根目錄下的目錄名數組 

                                foreach (string directoryName in isf.GetDirectoryNames()) 

                                        txtMsg.Text += directoryName + "\r\n"; 

                                txtMsg.Text += "根目錄下的檔案清單：\r\n"; 

                                // 擷取根目錄下的檔案名數組 

                                foreach (string fileName in isf.GetFileNames()) 

                                        txtMsg.Text += fileName + "\r\n"; 

                                txtMsg.Text += "目錄 Directory01 下的目錄清單：\r\n"; 

                                // 擷取 Directory01 目錄下的目錄名數組 

                                foreach (string directoryName in isf.GetDirectoryNames(subDirectory01)) 

                                txtMsg.Text += "目錄 Directory01/SubDirectory01 下的*.txt檔案清單：\r\n"; 

                                // 擷取 Directory01/SubDirectory01 目錄下的字尾名為 txt 的檔案名數組 

                                foreach (string fileName in isf.GetFileNames(System.IO.Path.Combine(subDirectory01, "*.txt"))) 

                                if (isf.FileExists(file01)) 

                                        // 在檔案 file01 中寫入内容 

                                        IsolatedStorageFileStream streamWrite = isf.OpenFile(file01, FileMode.Open, FileAccess.Write); 

                                        using (StreamWriter sw = new StreamWriter(streamWrite)) 

                                        { 

                                                sw.WriteLine("我是：webabcd"); 

                                                sw.WriteLine("我專注于asp.net, Silverlight"); 

                                        } 

                                        txtMsg.Text += "檔案 File01.txt 的内容：\r\n"; 

                                        // 讀取檔案 file01 中的内容 

                                        IsolatedStorageFileStream streamRead = isf.OpenFile(file01, FileMode.Open, FileAccess.Read); 

                                        using (StreamReader sr = new StreamReader(streamRead)) 

                                                txtMsg.Text += sr.ReadToEnd(); 

                                // 删除檔案 file01 

                                        isf.DeleteFile(file01); 

                                try 

                                        // 删除目錄 subDirectory01 

                                        isf.DeleteDirectory(subDirectory01); 

                                catch (IsolatedStorageException ex) 

                                        // IsolatedStorageException - 操作臨時存儲失敗時抛出的異常 

                                        // 因為 subDirectory01 目錄内還有檔案，是以會抛異常 

                                        txtMsg.Text += ex.Message; 

                        } 

                /// 示範 IsolatedStorageSettings 

                void Demo2() 

                        // IsolatedStorageSettings - 在獨立存儲中儲存的 key-value 字典表 

                        //         IsolatedStorageSettings.SiteSettings - 按站點儲存的 key-value 字典表 

                        //         IsolatedStorageSettings.ApplicationSettings - 按應用程式儲存的 key-value 字典表 

                        IsolatedStorageSettings iss = IsolatedStorageSettings.ApplicationSettings; 

                        // Add(key, value) - 添加一對 key-value 

                        iss.Add("key", "value"); 

                        txtMsg2.Text += (string)iss["key"] + "\r\n"; 

                        // 修改指定的 key 的 value 

                        iss["key"] = "value2"; 

                        // Remove(key) - 移除指定的 key 

                        // Count - 字典表内的總的 key-value 數 

                        iss.Remove("key"); 

                        txtMsg2.Text += iss.Count; 

                private void increase_Click(object sender, RoutedEventArgs e) 

                        // 示範獨立存儲的配額的相關操作 

                                // Quota - 目前配額（KB） 

                                // IncreaseQuotaTo(newQuotaSize) - 增加到指定的配額 

                                // AvailableFreeSpace - 目前的可用配額 

                                isf.IncreaseQuotaTo(isf.Quota + 1 * 1024 * 1024); 

                                System.Windows.Browser.HtmlPage.Window.Alert( 

                                        string.Format("目前配額：{0}；可用配額：{1}", isf.Quota, isf.AvailableFreeSpace)); 

                }    

        } 

}

示範 IsolatedStorageFile 的運作結果：

根目錄下的目錄清單：

Directory01

Directory02

根目錄下的檔案清單：

RootFile01.txt

__LocalSettings

目錄 Directory01 下的目錄清單：

SubDirectory01

目錄 Directory01/SubDirectory01 下的*.txt檔案清單：

File01.txt

File02.txt

檔案 File01.txt 的内容：

我是：webabcd

我專注于asp.net, Silverlight

無法删除，目錄不為空或不存在。

示範 IsolatedStorageSettings 的運作結果：

value

value2

OK

     本文轉自webabcd 51CTO部落格，原文連結：http://blog.51cto.com/webabcd/343094，如需轉載請自行聯系原作者