C＃文件复制回滚

Question

Does anyone know how to implement a rollback function in file copying when an exception is thrown.

Here are some conditions when I copy the files:

1. Copy the file to a shared folder
2. File is no greater than 3MB
3. File is an image file (jpg, jpeg, bmp, gif, png)
4. Prevention of file name duplicate is already implemented
5. OS is in Windows XP and higher
6. Code is on C# .Net 4.0 in Visual Studio 2010 Professional
7. Network connection is Local Area Network
8. Multiple files to copy, rollback when an exception is thrown

Please help. Thanks in advance.

Answer 1

Yes. Go back and delete all the files.

Depending on your structure, there are a variety of things you can do. If you have a List<string> , for example, iterate using an int :

for(int i = 0; i < filesToCopy.Count; i++) {
    try {
        // Copy the file
    } catch(Exception ex) {
        // Rollback
        while(--i >= 0) {
            System.IO.File.Delete(filesToCopy[i]); // For example
        }

        break;
    }
}

Answer 2

You can keep track of files copied successfully and delete every one of them when you decide to rollback. However, have you thought that your ability to modify files on the share in general (including deleting them during rollback) is dependent on the network connection?

In other words, you will never be able to rollback if the exception is due to the network going down -- unless there is another program under your control running on the other side that you can cooperate with.