在silverlight中使用IsolateStore隔离存储(下)

    
     在上一篇文章中, 介绍了如何使用隔离存储(Isolate Store) ,当然因为篇幅所限, 只用了其中的:    
     IsolatedStorageSettings
    
     因为它所提供的功能很有限, 而隔离存储所提供的是一整套本地存储的方案,包括目录,文件管理等方面.
本文将会继续上文中的内容,通过一个本地文件系统管理的DEMO来演示一下如果使用下面两个隔离存储类:

     IsolatedStorageFile (返回一个包括路径和文件的虚拟区域, 用于管理目录,文件等)
    
     IsolatedStorageFileStream (以流的方式读写指定路径的文件)
        
     首先请大家看一下这个DEMO的演示效果:

   
    
    
     我们可以在这里进行目录的选择,文件的选择,以及在相应的目录下添加,编辑,删除工作.而实现这些功能
都用到了上面所说的两个类.

    比如IsolatedStorageFile就提供了如下几个常用的方法:
    
    CreateDirectory() //创建路径 Creates a directory in the isolated storage scope. 
    CreateFile() //创建文件 Creates a file in the isolated store. 
    DeleteDirectory()//删除路径 Deletes a directory in the isolated storage scope. 
    DeleteFile() //删除文件

    GetDirectoryNames //获取指定路径下的目录列表
    GetFileNames //获取指定路径下的文件列表

    以及相应的路径文件检查方法:
    DirectoryExists() 
    FileExists()

    而另外的一个类是IsolatedStorageFileStream, 它主要是对给定路径下的文件进行流读写操作,我们可以
使用如下方法将其绑定了一个读或写的流对象上:

IsolatedStorageFileStream subDraftFile = store.CreateFile(filePath);

using (StreamWriter writer = new StreamWriter(subDraftFile))
{
    //
}

     好的,下面是这个DEMO的page.xaml文件代码:

<Grid x:Name="LayoutRoot" Background="AntiqueWhite" >
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="0.307*"/>
        <ColumnDefinition Width="0.176*" />
        <ColumnDefinition Width="0.517*"/>
    </Grid.ColumnDefinitions>

    <Grid.RowDefinitions>
        <RowDefinition  Height="40"/>
        <RowDefinition  Height="40"/>
        <RowDefinition  Height="231"/>
        <RowDefinition Height="*"/>
    </Grid.RowDefinitions>

    <StackPanel  Orientation="Vertical" Grid.Row="0"   Grid.Column="0"  Grid.RowSpan="4" Background="AliceBlue" >
        <TextBlock Grid.Row="0" Grid.Column="1"   HorizontalAlignment="Stretch" Margin="5,5,5,5">
         <Run Text="路径:"/>
        </TextBlock>
        <ListBox x:Name="DirectoryList" SelectionChanged="DirectoryList_SelectionChanged" Margin="5,5,5,5"/>
        <TextBlock Grid.Row="0" Grid.Column="1"   HorizontalAlignment="Stretch" Margin="5,5,5,5">
         <Run Text="文件列表:"/>
        </TextBlock>
        <ListBox x:Name="FileList"  SelectionChanged ="FileList_SelectionChanged" Margin="5,5,5,5" Height="150"/>
   </StackPanel>
   
        <TextBlock Grid.Row="0" Grid.Column="1"   HorizontalAlignment="Stretch" Margin="5,5,5,5">
         <Run Text="收件人:"/>
        </TextBlock>
        <TextBox x:Name="Recipient"  Width="200" Grid.Row="0" Grid.Column="2"  Margin="5,5,5,5" HorizontalAlignment="Left"  d:LayoutOverrides="GridBox"/>

        <TextBlock Grid.Row="1" Grid.Column="1"  HorizontalAlignment="Stretch" Margin="5,5,5,5">
         <Run Text="主 题:"/>
        </TextBlock>
        <TextBox x:Name="Subject"  Width="200" Grid.Row="1" Grid.Column="2" Margin="5,5,5,5" HorizontalAlignment="Left"  d:LayoutOverrides="GridBox"/>

        <TextBlock Grid.Row="2" Grid.Column="1" HorizontalAlignment="Stretch" Margin="5,5,5,5">
         <Run Text="内 容:"/>
        </TextBlock>
        <TextBox x:Name="Body" TextWrapping="Wrap"  Grid.Row="2" Grid.Column="2" Margin="5,5,5,5" HorizontalAlignment="Stretch"  Grid.RowSpan="1" d:LayoutOverrides="GridBox" RenderTransformOrigin="0.5,0.5">
         </TextBox>

    <StackPanel  Grid.Row="3"  Orientation="Horizontal" Grid.Column="1"  Grid.ColumnSpan="2" Margin="0,0,0,8">
        <Button x:Name="AddToDraft" Margin="5,5,5,5" Content=" 添加草稿 " Click="AddToDraft_Click" />
        <Button x:Name="SaveToDraft" Margin="5,5,5,5" Content=" 编辑草稿 " Click="SaveToDraft_Click" />
        <Button x:Name="DeleteDraft" Margin="5,5,5,5" Content=" 删除当前草稿 " Click="DeleteDraft_Click"/>
    </StackPanel>
</Grid>

    
     而相应的page.xaml.cs文件如下(相关内容见注释):  

public partial class Page : UserControl
{
    public Page()
    {
        InitializeComponent();
        this.Loaded += new RoutedEventHandler(Page_Loaded);
    }

    void Page_Loaded(object sender, RoutedEventArgs e)
    {
        using (var store = System.IO.IsolatedStorage.IsolatedStorageFile.GetUserStoreForApplication())
        {
            //如果本地没有文件夹,则初始化本地文件夹信息
            if (!store.DirectoryExists("本地文件夹"))
            {
                // 在当前根目录下创建三个目录
                store.CreateDirectory("本地文件夹");

                // 可使用下面方面在指定目录下创建子目录
                store.CreateDirectory(System.IO.Path.Combine("本地文件夹", "收件箱"));
                store.CreateDirectory(System.IO.Path.Combine("本地文件夹", "发件箱"));
                store.CreateDirectory(System.IO.Path.Combine("本地文件夹", "草稿箱"));
            }

            //加载文件夹信息到控件
            foreach (string directory in GetAllDirectories("*", store))
            {
                DirectoryList.Items.Add(directory);
            }
        }
    }

    /// <summary>
    /// 添加数据到草稿箱
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    private void AddToDraft_Click(object sender, RoutedEventArgs e)
    {
        using (var store = System.IO.IsolatedStorage.IsolatedStorageFile.GetUserStoreForApplication())
        {
            string filePath = DirectoryList.SelectedItem.ToString();
            if (store.DirectoryExists(filePath))
            {
                filePath = System.IO.Path.Combine(filePath, Subject.Text + ".txt");

                if (!store.FileExists(filePath))
                {
                    IsolatedStorageFileStream subDraftFile = store.CreateFile(filePath);

                    using (StreamWriter writer = new StreamWriter(subDraftFile))
                    {
                        writer.WriteLine("Recipient:" + Recipient.Text);
                        writer.WriteLine("Subject:" + Subject.Text);
                        writer.WriteLine("Body:" + Body.Text);
                    }

                    subDraftFile.Close();
                }
                else
                {
                    HtmlPage.Window.Alert("文件已存在,请修改主题后再进行保存");
                }
            }
        }
       
    }
    /// <summary>
    /// 保存草稿箱的数据
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    private void SaveToDraft_Click(object sender, RoutedEventArgs e)
    {
        using (var store = System.IO.IsolatedStorage.IsolatedStorageFile.GetUserStoreForApplication())
        {
            string filePath = DirectoryList.SelectedItem.ToString() + "/" + FileList.SelectedItem.ToString();

            if (store.FileExists(filePath))
            {
                store.DeleteFile(filePath);
                IsolatedStorageFileStream subDraftFile = store.CreateFile(filePath);

                using (StreamWriter writer = new StreamWriter(subDraftFile))
                {
                    writer.WriteLine("Recipient:" + Recipient.Text);
                    writer.WriteLine("Subject:" + Subject.Text);
                    writer.WriteLine("Body:" + Body.Text);
                }

                subDraftFile.Close();
            }
            else
            {
                HtmlPage.Window.Alert("要修改的当前文件不在本地隔离存储!!!");
            }
           
        }
    }

    /// <summary>
    /// 删除指定草稿
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    private void DeleteDraft_Click(object sender, RoutedEventArgs e)
    {
        if (FileList.SelectedItem != null)
        {
            using (var store = System.IO.IsolatedStorage.IsolatedStorageFile.GetUserStoreForApplication())
            {
                string filePath = DirectoryList.SelectedItem.ToString() + "/" + FileList.SelectedItem.ToString();
                if (store.FileExists(filePath))
                {
                    if (HtmlPage.Window.Confirm("是否删除文件: " + filePath))
                    {
                        store.DeleteFile(filePath);
                    }
                }
            }
        }
    }


    /// <summary>
    /// 分割字符串
    /// </summary>
    public static string[] SplitString(string strContent, string strSplit)
    {
        if (strContent != null && strContent != "")
        {
            if (strContent.IndexOf(strSplit) < 0)
            {
                string[] tmp = { strContent };
                return tmp;
            }
            return Regex.Split(strContent, Regex.Escape(strSplit), RegexOptions.IgnoreCase);
        }
        else
        {
            return new string[0] { };
        }
    }

    /// <summary>
    /// 下面代码从网上获得,用于递归指定路径下的所有目录
    /// </summary>
    /// <param name="pattern"></param>
    /// <param name="storeFile"></param>
    /// <returns></returns>
    public string[] GetAllDirectories(string pattern, System.IO.IsolatedStorage.IsolatedStorageFile storeFile)
    {
        // Get the root of the search string.
        string root = System.IO.Path.GetDirectoryName(pattern);

        if (root != "") root += "/";

        // Retrieve directories.
        string[] directories;

        directories = storeFile.GetDirectoryNames(pattern);

        List<string> directoryList = new List<string>(directories);

        // Retrieve subdirectories of matches.
        for (int i = 0, max = directories.Length; i < max; i++)
        {
            string directory = directoryList[i] + "/";
            string[] more = GetAllDirectories(root + directory + "*", storeFile);

            // For each subdirectory found, add in the base path.

            for (int j = 0; j < more.Length; j++)
                more[j] = directory + more[j];

            // Insert the subdirectories into the list and 
            // update the counter and upper bound.

            directoryList.InsertRange(i + 1, more);
            i += more.Length;
            max += more.Length;
        }

        return (string[])directoryList.ToArray();
    }

    /// <summary>
    /// 下面代码从网上获得,用于递归指定路径下的所有文件
    /// </summary>
    /// <param name="pattern"></param>
    /// <param name="storeFile"></param>
    /// <returns></returns>
    public string[] GetAllFiles(string pattern, System.IO.IsolatedStorage.IsolatedStorageFile storeFile)
    {
        // Get the root and file portions of the search string.
        string fileString = System.IO.Path.GetFileName(pattern);

        string[] files;
        files = storeFile.GetFileNames(pattern);

        List<string> fileList = new List<string>(files);

        // Loop through the subdirectories, collect matches, 
        // and make separators consistent.

        //foreach (string directory in GetAllDirectories("*", storeFile))
        //    foreach (string file in storeFile.GetFileNames(directory + "/" + fileString))
        //        fileList.Add((directory + "/" + file));

        return (string[])fileList.ToArray();
    }

    /// <summary>
    /// 当用户选择不同的路径时
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    private void DirectoryList_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        FileList.Items.Clear();

        using (var store = System.IO.IsolatedStorage.IsolatedStorageFile.GetUserStoreForApplication())
        {
            foreach (string file in GetAllFiles(DirectoryList.SelectedItem.ToString() + "/", store))
            {
                FileList.Items.Add(file);
            }
        }
    }

    /// <summary>
    /// 当用户选择相应的文件时
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    private void FileList_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        if(FileList.SelectedItem != null)
        {
            using (var store = System.IO.IsolatedStorage.IsolatedStorageFile.GetUserStoreForApplication())
            {
                string filePath = System.IO.Path.Combine(DirectoryList.SelectedItem.ToString(), FileList.SelectedItem.ToString());

                if (store.FileExists(filePath))
                {
                    IsolatedStorageFileStream subDraftFile =
                        store.OpenFile(filePath, FileMode.Open);
                    //加载指定文件中的内容
                    using (StreamReader reader = new StreamReader(subDraftFile))
                    {
                        string[] emailInfo = SplitString(reader.ReadToEnd(), "\r\n");
                        foreach (string emailItem in emailInfo)
                        {
                            if (emailItem.IndexOf("Recipient") >= 0)
                            {
                                Recipient.Text = emailItem.Split(':')[1]; continue;
                            }
                            if (emailItem.IndexOf("Subject") >= 0)
                            {
                                Subject.Text = emailItem.Split(':')[1]; continue;
                            }
                            if (emailItem.IndexOf("Body") >= 0)
                            {
                                Body.Text = emailItem.Split(':')[1]; continue;
                            }
                        }

                    }
                    subDraftFile.Close();
                }
                else
                {
                    HtmlPage.Window.Alert("文件: " + filePath + " 不存在!!!");
                }
            }                
        }
    }    
}

      其实就我个人而言,我是不太建议过于频繁的使用Isolate Store, 当然主要是出于安全问题的考虑(
因为我本人对它的机制还不是很了解,所以不便妄加评论), 但我本人还是比较偏向于下面这篇文章中的观
点:

     临时数据存储可以考虑的方法——IsolatedStorage      

     好了,今天的内容就先到这里了:)
   
     源代码下载链接, 请点击这里:)