[C#]UnauthorizedAccessException

當我們用Directory.GetFiles() 在特定路徑下尋找檔案時,

若不幸程式存取到系統資料夾時(列如: System Volume Information), 則程式可能中斷並跳出 UnauthorizedAccessException 的錯誤訊息

避免的方式很簡單,  

建議先不要找檔案,先找資料夾

Directory.GetDirectories(Path.GetDirectoryName(System.Reflection.Assembly.GetEntryAssembly().Location), "*" ,SearchOption.TopDirectoryOnly);

過濾系統資料夾

if(d.Contains("System Volume Information"))continue;

if (new FileInfo(d).Attributes == FileAttributes.System) continue;

if (new FileInfo(d).Attributes == FileAttributes.Hidden) continue;

再去尋訪剩下的資料夾, 並找出指定的檔案 (SearchPattern )

fls = Directory.GetFiles(d, SearchPattern, SearchOption.AllDirectories);

將結果合併成一個List 並輸出

if (fls != null) files = files.Concat(fls).ToList<string>();

完整 Sample code 如下:

var dirs= Directory.GetDirectories(Path.GetDirectoryName(System.Reflection.Assembly.GetEntryAssembly().Location), "*" ,SearchOption.TopDirectoryOnly);                          List<string> files = new List<string>();              foreach (string d in dirs)              {                                    if (d.Contains("System Volume Information")) continue;                  if (new FileInfo(d).Attributes == FileAttributes.System) continue;                  if (new FileInfo(d).Attributes == FileAttributes.Hidden) continue;                  string[] fls = null;                  try                  {                      fls = Directory.GetFiles(d, SearchPattern , SearchOption.AllDirectories);                      if (fls != null) files = files.Concat(fls).ToList<string>();                  }                  catch (Exception ex)                  {                  }                                                 }