c# - 一种优雅的重命名文件的方法，如果它在归档时已经存在

Question

我想编写一个归档函数，将文件夹中的所有文件移动到使用当前日期的归档子文件夹中。该过程可能在一天内运行多次，因此需要处理重复项。

归档规则如下:

1. 如果文件名已经存在，我想添加下划线“_”和一个数字(从 1 开始)。
2. 如果文件名已经被修改了我想增加数字。

我可以使用大量 File.Exist 和 LastIndexOf 调用来做到这一点，但是有没有更优雅的方法？也许用 LINQ？

编辑:

这是我已有的代码。它有点粗糙和准备就绪，但它给出了我想要做什么的想法。

/// <summary>
/// Move the local file into the archive location.
/// If the file already exists then add a counter to the file name or increment the existing counter
/// </summary>
/// <param name="LocalFilePath">The full path of the file to be archived</param>
/// <param name="ArchiveFilePath">The proposed full path of the file once it's been archived</param>
private void ArchiveFile(string LocalFilePath, string ArchiveFilePath)
{
    // Ensure the file name doesn't already exists in the location we want to move it to
    if (File.Exists(ArchiveFilePath) == true)
    {
        // Does the archive file have a number at the end?
        string[] archiveSplit = Path.GetFileNameWithoutExtension(ArchiveFilePath).Split('_');
        if( archiveSplit.Length == 1)
        {
            // No number detected so append the number 1 to the filename
            string newArcFileName = string.Format("{0}_1.{1}",
                Path.GetFileNameWithoutExtension(ArchiveFilePath), Path.GetExtension(ArchiveFilePath));

            // Create the new full path
            string newArcPath = Path.Combine(Path.GetDirectoryName(ArchiveFilePath), newArcFileName);

            // recursively call the archive folder to ensure the new file name doesn't exist before moving
            ArchiveFile( LocalFilePath, newArcPath);
        }
        else
        {
            // Get the number of the last element of the split
            int lastNum = Convert.ToInt32( archiveSplit.Last().Substring(1) ) +1;

            // Rebuild the filename using the incremented number
            string newArcFileName = archiveSplit[0];
            for (int i = 1; i < archiveSplit.Length; i++)
            {
                newArcFileName += archiveSplit[i];
            }
            // finally add the number and extension
            newArcFileName = string.Format("{0}_{1}.{2}", newArcFileName, lastNum, Path.GetExtension(ArchiveFilePath));

            // Create the new full path
            string newArcPath = Path.Combine(Path.GetDirectoryName(ArchiveFilePath), newArcFileName);

            // recursively call the archive folder to ensure the new file name doesn't exist before moving
            ArchiveFile(LocalFilePath, newArcPath);
        }
    }
    else
    {
        // There is no file with a matching name
        File.Move(LocalFilePath, ArchiveFilePath);
    }
}

Answer 1

Directory 类有一个方法来接收其中所有文件的列表。该方法允许您指定过滤字符串，如下所示:

Directory.GetFiles(directoryPath, filterString);

如果您已经知道文件名前缀，则可以使用该过滤器字符串来获取该模式内的所有文件:

filterString = string.Format("{0}_*.{1}", defaultFileNameWithoutExtension, defaultExtension);

然后您可以简单地选择后缀最高的那个，提取后缀数字，增加它并构建新的(未使用的)文件名。

免责声明:这是用心写的，如有错误，请随时编辑:)