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:)