public bool IsDirectory(string path) {
    return string.IsNullOrEmpty(Path.GetFileName(path)) || Directory.Exists(path);
}

检查路径文件名是否为空字符串，或者目录是否存在。这样就不会出现文件属性错误，同时仍然为可能存在的故障提供冗余。

在结合其他答案的建议后，我意识到我得到了和罗尼·奥弗比的答案差不多的东西。以下是一些测试，指出一些需要考虑的问题:

文件夹可以有扩展名:C:\Temp\folder_with.dot 文件不能以目录分隔符(斜杠)结束 从技术上讲，有两个特定于平台的目录分隔符——也就是说，可能是斜杠，也可能不是。和Path.AltDirectorySeparatorChar)

测试(Linqpad)

var paths = new[] {
    // exists
    @"C:\Temp\dir_test\folder_is_a_dir",
    @"C:\Temp\dir_test\is_a_dir_trailing_slash\",
    @"C:\Temp\dir_test\existing_folder_with.ext",
    @"C:\Temp\dir_test\file_thats_not_a_dir",
    @"C:\Temp\dir_test\notadir.txt",
    // doesn't exist
    @"C:\Temp\dir_test\dne_folder_is_a_dir",
    @"C:\Temp\dir_test\dne_folder_trailing_slash\",
    @"C:\Temp\dir_test\non_existing_folder_with.ext",
    @"C:\Temp\dir_test\dne_file_thats_not_a_dir",
    @"C:\Temp\dir_test\dne_notadir.txt",        
};

foreach(var path in paths) {
    IsFolder(path/*, false*/).Dump(path);
}

结果

C:\Temp\dir_test\folder_is_a_dir
  True 
C:\Temp\dir_test\is_a_dir_trailing_slash\
  True 
C:\Temp\dir_test\existing_folder_with.ext
  True 
C:\Temp\dir_test\file_thats_not_a_dir
  False 
C:\Temp\dir_test\notadir.txt
  False 
C:\Temp\dir_test\dne_folder_is_a_dir
  True 
C:\Temp\dir_test\dne_folder_trailing_slash\
  True 
C:\Temp\dir_test\non_existing_folder_with.ext
  False (this is the weird one)
C:\Temp\dir_test\dne_file_thats_not_a_dir
  True 
C:\Temp\dir_test\dne_notadir.txt
  False 

方法

/// <summary>
/// Whether the <paramref name="path"/> is a folder (existing or not); 
/// optionally assume that if it doesn't "look like" a file then it's a directory.
/// </summary>
/// <param name="path">Path to check</param>
/// <param name="assumeDneLookAlike">If the <paramref name="path"/> doesn't exist, does it at least look like a directory name?  As in, it doesn't look like a file.</param>
/// <returns><c>True</c> if a folder/directory, <c>false</c> if not.</returns>
public static bool IsFolder(string path, bool assumeDneLookAlike = true)
{
    // https://stackoverflow.com/questions/1395205/better-way-to-check-if-path-is-a-file-or-a-directory
    // turns out to be about the same as https://stackoverflow.com/a/19596821/1037948

    // check in order of verisimilitude

    // exists or ends with a directory separator -- files cannot end with directory separator, right?
    if (Directory.Exists(path)
        // use system values rather than assume slashes
        || path.EndsWith("" + Path.DirectorySeparatorChar)
        || path.EndsWith("" + Path.AltDirectorySeparatorChar))
        return true;

    // if we know for sure that it's an actual file...
    if (File.Exists(path))
        return false;

    // if it has an extension it should be a file, so vice versa
    // although technically directories can have extensions...
    if (!Path.HasExtension(path) && assumeDneLookAlike)
        return true;

    // only works for existing files, kinda redundant with `.Exists` above
    //if( File.GetAttributes(path).HasFlag(FileAttributes.Directory) ) ...; 

    // no idea -- could return an 'indeterminate' value (nullable bool)
    // or assume that if we don't know then it's not a folder
    return false;
}

我在遇到类似的问题时遇到过这个问题，只不过我需要检查一个文件或文件夹的路径是否为文件或文件夹，而该文件或文件夹可能实际上并不存在。上面有一些关于答案的评论，提到它们不适用于这种情况。我找到了一个解决方案(我使用VB。NET，但你可以转换，如果你需要)，这似乎很适合我:

Dim path As String = "myFakeFolder\ThisDoesNotExist\"
Dim bIsFolder As Boolean = (IO.Path.GetExtension(path) = "")
'returns True

Dim path As String = "myFakeFolder\ThisDoesNotExist\File.jpg"
Dim bIsFolder As Boolean = (IO.Path.GetExtension(path) = "")
'returns False

希望这能对别人有所帮助!

这是我的解决方案，注意，我正在寻找一个函数，严格避免任何不必要的文件系统访问，但这里只允许字符串操作(路径可能不存在):

public static bool IsFolder(string path)
{
    if (string.IsNullOrEmpty(path)) return false;
    if (path.EndsWith("\\")) return true;
    return (path.Contains("\\") && string.IsNullOrEmpty(Path.GetExtension(path)));
}

using System;
using System.IO;
namespace FileOrDirectory
{
     class Program
     {
          public static string FileOrDirectory(string path)
          {
               if (File.Exists(path))
                    return "File";
               if (Directory.Exists(path))
                    return "Directory";
               return "Path Not Exists";
          }
          static void Main()
          {
               Console.WriteLine("Enter The Path:");
               string path = Console.ReadLine();
               Console.WriteLine(FileOrDirectory(path));
          }
     }
}

这样不行吗?

var isFile = Regex.IsMatch(path, @"\w{1,}\.\w{1,}$");