c# - 即使调用应用程序关闭，删除功能也会删除

Question

我遇到了一个奇怪的问题(这可能是我缺乏知识)，我展示了有问题的代码:

try
{
    f.Delete();
    fTemp.MoveTo(f.FullName);
    Console.WriteLine("INFO: Old file deleted new file moved in > {0}", f.FullName);
}
catch (IOException ex)
{
    Console.WriteLine("ERROR: Output file has IO exception > {0}", f.FullName);
    Environment.ExitCode = 1;
}

f 和 fTemp 是 FileInfo 对象。因此，如果我使用代码运行它，其中 f 是在媒体播放器中播放的视频文件，它会抛出异常。效果很好，符合预期。现在，当我关闭媒体播放器时，它会删除文件!？即使我的应用程序已关闭很长时间。即使我关闭 Visual Studio，它仍然会在我关闭媒体播放器时删除该文件。好像在某处设置了一些回调以确保文件在某个时候被删除。这种不受欢迎的行为。但我不知道到底出了什么问题......

现在的结果:

if (!IsFileLocked(f))
{
    try
    {
        f.Delete();
        fTemp.MoveTo(f.FullName);
        Console.WriteLine("INFO: Old file deleted new file moved in > {0}", f.FullName);
    }
    catch (IOException ex)
    {
        Console.WriteLine("ERROR: Output file has IO exception > {0}", f.FullName);
        Environment.ExitCode = 1;

    }

    catch (UnauthorizedAccessException ex)
    {
        Environment.ExitCode = 2;
        Console.WriteLine("ERROR: Output file is locked > {0}", f.FullName);

    }
}
else
{
    Environment.ExitCode = 3;
    Console.WriteLine("ERROR: Couldn't delete file was locked");

}

我知道我仍然可以在 Delete 和 MoveTo 之间做得更好，但我现在将进行更改，shotgun 编码......

Answer 1

您将收到 IOException，因为无法立即删除或写入文件。但是，当您调用 Delete() 时，似乎正在调用文件以进行删除。

虽然媒体播放器在文件打开时阻止文件被删除，但文件在关闭时仍被标记为删除，无论您的程序是否正在运行。因此，当媒体播放器关闭时，文件将被删除。

您可以使用以下代码检查文件是否正在使用，代码取自 here .使 Delete 和 Copy 以未被锁定为条件，你应该没问题。

try
{
    if(!IsFileLocked(f))
    {
        f.Delete();
        fTemp.MoveTo(f.FullName);
        Console.WriteLine("INFO: Old file deleted new file moved in > {0}", f.FullName);
    }
}

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;
}