Deleting files in use

Question

I created a simple program to delete temporary files in C# (for fun, not a major project) and am running into locked files (in use) issues. How do you normally either exclude those files? For reference I am receiving the error:

The process cannot access the file 'ExchangePerflog_8484fa31c65c7a31cfcccd43.dat' because it is being used by another process.

Code:

static void Main(string[] args)     {         string folderPath = string.Empty;         folderPath = System.Environment.GetEnvironmentVariable("temp");         deleteFilesInDirectory(folderPath);     }      public static void deleteFilesInDirectory(string folderPath)      {          try         {             var dir = new DirectoryInfo(folderPath);             dir.Attributes = dir.Attributes & ~FileAttributes.ReadOnly;             dir.Delete(true);             MessageBox.Show(folderPath + " has been cleaned.");         }         catch (System.IO.IOException ex)         {             MessageBox.Show(ex.Message);              return;          }      }      

Answer 1

Description

There is no way to delete a file that is currently in use by another process. But you can wait till the file is not locked.

Check in a while loop till the file is unlocked with this method

protected virtual bool IsFileLocked(FileInfo file) {     FileStream stream = null;      try     {         stream = file.Open(FileMode.Open, FileAccess.ReadWrite, FileShare.None);     }     catch (IOException)     {         //the file is unavailable because it is:         //still being written to         //or being processed by another thread         //or does not exist (has already been processed)         return true;     }     finally     {         if (stream != null)             stream.Close();     }      //file is not locked     return false; } 

Sample

FileInfo file = new FileInfo("PathToTheFile"); while (IsFileLocked(file))     Thread.Sleep(1000); file.Delete(); 

Update

If you want to skip locked files you can do this.

// var dir = new DirectoryInfo(folderPath); foreach(var file in dir.GetFiles()) {     try     {         file.Delete();     }     catch (IOException)     {         //file is currently locked     } } 

Answer 2

Try the following code. Just add two lines before file deletion:

GC.Collect(); GC.WaitForPendingFinalizers();