vb.net FindFirstFile 与 IO.Directory.GetFiles

FindFirstFile with IO.Directory.GetFiles

提问by Wine Too

I have a situation where I have to find a path to the first file named my.exestarting from startingdirectory& \mydir\and go deep as needed.
Actually, IO.Directory.GetFilesis suitable but I need it stop searching after the first file is found like it is possible with FindFirstFilefrom WinAPI.

我有一种情况，我必须找到my.exe从startingdirectory&开始命名的第一个文件的路径，\mydir\并根据需要深入。
实际上，IO.Directory.GetFiles是合适的，但我需要它在找到第一个文件后停止搜索，就像FindFirstFile从 WinAPI 中可以做到的那样。

VB.NET

网络

Dim findedDirectories() As String = IO.Directory.GetFiles( _
startingdirectory & "\mydir\", "my.exe", IO.SearchOption.AllDirectories)

C#

C＃

string[] findedDirectories = IO.Directory.GetFiles( _
startingdirectory + "\mydir\", "my.exe", IO.SearchOption.AllDirectories);

Is it possible to stop searching after the first file is found in a way that the result of the function will be a stringor an empty string, not a string array? Or is here better way to search for a first file in subdirectories?

是否可以在找到第一个文件后以函数结果为 astring或 anempty string而不是 a的方式停止搜索string array？或者这里有更好的方法来搜索子目录中的第一个文件？

回答by Markus Safar

A solution like the following one could help:

像下面这样的解决方案可能会有所帮助：

/// <summary>
/// Searches for the first file matching to searchPattern in the sepcified path.
/// </summary>
/// <param name="path">The path from where to start the search.</param>
/// <param name="searchPattern">The pattern for which files to search for.</param>
/// <returns>Either the complete path including filename of the first file found
/// or string.Empty if no matching file could be found.</returns>
public static string FindFirstFile(string path, string searchPattern)
{
    string[] files;

    try
    {
        // Exception could occur due to insufficient permission.
        files = Directory.GetFiles(path, searchPattern, SearchOption.TopDirectoryOnly);
    }
    catch (Exception)
    {
        return string.Empty;
    }

    // If matching files have been found, return the first one.
    if (files.Length > 0)
    {
        return files[0];
    }
    else
    {
        // Otherwise find all directories.
        string[] directories;

        try
        {
            // Exception could occur due to insufficient permission.
            directories = Directory.GetDirectories(path);
        }
        catch (Exception)
        {
            return string.Empty;
        }

        // Iterate through each directory and call the method recursivly.
        foreach (string directory in directories)
        {
            string file = FindFirstFile(directory, searchPattern);

            // If we found a file, return it (and break the recursion).
            if (file != string.Empty)
            {
                return file;
            }
        }
    }

    // If no file was found (neither in this directory nor in the child directories)
    // simply return string.Empty.
    return string.Empty;
}

回答by David Heffernan

I guess the simplest approach would be to organise the recursion into sub-directories yourself with recursive calls to Directory.GetDirectoriespassing SearchOption.TopDirectoryOnly. In each directory check for the file's existence with File.Exists.

我想最简单的方法是递归自己与递归调用组织成子目录Directory.GetDirectories传递SearchOption.TopDirectoryOnly。在每个目录中检查文件是否存在File.Exists。

This actually mirrors the way it would be done in Win32 with FindFirstFile. When using FindFirstFileyou always need to implement the sub-directory recursion yourself because FindFirstFilehas nothing analagous to SearchOption.AllDirectories.

这实际上反映了在 Win32 中使用FindFirstFile. 使用时，FindFirstFile您总是需要自己实现子目录递归，因为FindFirstFile与SearchOption.AllDirectories.