FindFirstFile 与 IO.Directory.GetFiles

Question

我有一种情况，我必须从 startingdirectory 和 \mydir\ 开始找到名为 my.exe 的第一个文件的路径，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 WinAPI 中的 FindFirstFile 一样。

VB.NET

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

C#

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

是否可以在找到第一个文件后停止搜索，以使函数的结果将是string 或empty string，而不是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？

Answer 1

类似以下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;
}

Answer 2

我想最简单的方法是通过递归调用Directory.GetDirectories 传递SearchOption.TopDirectoryOnly，自己将递归组织到子目录中。在每个目录中使用File.Exists 检查文件是否存在。

这实际上反映了在 Win32 中使用FindFirstFile 的方式。使用FindFirstFile 时，您始终需要自己实现子目录递归，因为FindFirstFile 与SearchOption.AllDirectories 没有任何相似之处。