使用條目填充後清除ObservableCollection

Question

我有以下代碼來使用驅動器（RootDrive）和目錄填充Treeview。 但是，如何在每個循環之後清除目錄集合？現在發生的是全部目錄全部驅動器被添加到每個驅動器。 當我在Finally語句中使用directories.Clear（）時，沒有添加到每個驅動器的目錄。

static public ObservableCollection<GetDrive> RootDrive = new ObservableCollection<GetDrive>(); 

public MainWindow() 
{ 
    InitializeComponent(); 

    ObservableCollection<GetDirectory>directories = new ObservableCollection<GetDirectory>(); 

    foreach (DriveInfo di in DriveInfo.GetDrives()) 
    { 
     try 
     { 
      foreach (string s in Directory.GetDirectories(di.Name)) 
      { 
       directories.Add(new GetDirectory(s)); 
      }    
     } 

     catch (IOException) //drive is not ready, e.g. DVD drive 
     { 

     } 

     finally 
     { 
      RootDrive.Add(new GetDrive(di.Name, directories)); 
      directories.Clear(); 
     } 
    } 
} 

} 

}

Answer 1

簡而言之，使用本地變量。你濫用finally指令。

static public ObservableCollection<GetDrive> RootDrive = new ObservableCollection<GetDrive>(); 

public MainWindow() 
{ 
    InitializeComponent(); 

    foreach (DriveInfo di in DriveInfo.GetDrives()) 
    { 
     ObservableCollection<GetDirectory>directories = new ObservableCollection<GetDirectory>(); 
     try 
     { 
      foreach (string s in Directory.GetDirectories(di.Name)) 
      { 
       directories.Add(new GetDirectory(s)); 
      }    
     } 
     catch (IOException) //drive is not ready, e.g. DVD drive 
     { 
      // Handle it? 
     }  
     RootDrive.Add(new GetDrive(di.Name, directories)); 
    } 
} 

Answer 2

我認爲你必須更改代碼位和第一個for循環之後添加明確的方法。像下面...

static public ObservableCollection<GetDrive> RootDrive = new ObservableCollection<GetDrive>(); 

public MainWindow() 
{ 
    InitializeComponent(); 


    foreach (DriveInfo di in DriveInfo.GetDrives()) 
    { 
     try 
     { 
      directories.Clear(); 
      foreach (string s in Directory.GetDirectories(di.Name)) 
      { 
       directories.Add(new GetDirectory(s)); 
      }    
     } 

     catch (IOException) //drive is not ready, e.g. DVD drive 
     { 

     } 

     finally 
     { 
      RootDrive.Add(new GetDrive(di.Name, directories)); 

     } 
    } 
} 

}