最准确的方法是使用shlwapi.dll中的一些互操作代码

[DllImport(SHLWAPI, CharSet = CharSet.Unicode)]
[return: MarshalAsAttribute(UnmanagedType.Bool)]
[ResourceExposure(ResourceScope.None)]
internal static extern bool PathIsDirectory([MarshalAsAttribute(UnmanagedType.LPWStr), In] string pszPath);

然后你可以这样调用它:

#region IsDirectory
/// <summary>
/// Verifies that a path is a valid directory.
/// </summary>
/// <param name="path">The path to verify.</param>
/// <returns><see langword="true"/> if the path is a valid directory; 
/// otherwise, <see langword="false"/>.</returns>
/// <exception cref="T:System.ArgumentNullException">
/// <para><paramref name="path"/> is <see langword="null"/>.</para>
/// </exception>
/// <exception cref="T:System.ArgumentException">
/// <para><paramref name="path"/> is <see cref="F:System.String.Empty">String.Empty</see>.</para>
/// </exception>
public static bool IsDirectory(string path)
{
    return PathIsDirectory(path);
}

这是我的:

    bool IsPathDirectory(string path)
    {
        if (path == null) throw new ArgumentNullException("path");
        path = path.Trim();

        if (Directory.Exists(path)) 
            return true;

        if (File.Exists(path)) 
            return false;

        // neither file nor directory exists. guess intention

        // if has trailing slash then it's a directory
        if (new[] {"\\", "/"}.Any(x => path.EndsWith(x)))
            return true; // ends with slash

        // if has extension then its a file; directory otherwise
        return string.IsNullOrWhiteSpace(Path.GetExtension(path));
    }

这与别人的答案相似，但并不完全相同。

很晚才到这里，但我发现Nullable<Boolean>返回值相当难看- IsDirectory(字符串路径)返回null并不等于没有详细注释的不存在的路径，所以我提出了以下内容:

public static class PathHelper
{
    /// <summary>
    /// Determines whether the given path refers to an existing file or directory on disk.
    /// </summary>
    /// <param name="path">The path to test.</param>
    /// <param name="isDirectory">When this method returns, contains true if the path was found to be an existing directory, false in all other scenarios.</param>
    /// <returns>true if the path exists; otherwise, false.</returns>
    /// <exception cref="ArgumentNullException">If <paramref name="path"/> is null.</exception>
    /// <exception cref="ArgumentException">If <paramref name="path"/> equals <see cref="string.Empty"/></exception>
    public static bool PathExists(string path, out bool isDirectory)
    {
        if (path == null) throw new ArgumentNullException(nameof(path));
        if (path == string.Empty) throw new ArgumentException("Value cannot be empty.", nameof(path));

        isDirectory = Directory.Exists(path);

        return isDirectory || File.Exists(path);
    }
}

这个helper方法写得足够冗长和简洁，以便在第一次阅读时就能理解其意图。

/// <summary>
/// Example usage of <see cref="PathExists(string, out bool)"/>
/// </summary>
public static void Usage()
{
    const string path = @"C:\dev";

    if (!PathHelper.PathExists(path, out var isDirectory))
        return;

    if (isDirectory)
    {
        // Do something with your directory
    }
    else
    {
        // Do something with your file
    }
}

最准确的方法是使用shlwapi.dll中的一些互操作代码

[DllImport(SHLWAPI, CharSet = CharSet.Unicode)]
[return: MarshalAsAttribute(UnmanagedType.Bool)]
[ResourceExposure(ResourceScope.None)]
internal static extern bool PathIsDirectory([MarshalAsAttribute(UnmanagedType.LPWStr), In] string pszPath);

然后你可以这样调用它:

#region IsDirectory
/// <summary>
/// Verifies that a path is a valid directory.
/// </summary>
/// <param name="path">The path to verify.</param>
/// <returns><see langword="true"/> if the path is a valid directory; 
/// otherwise, <see langword="false"/>.</returns>
/// <exception cref="T:System.ArgumentNullException">
/// <para><paramref name="path"/> is <see langword="null"/>.</para>
/// </exception>
/// <exception cref="T:System.ArgumentException">
/// <para><paramref name="path"/> is <see cref="F:System.String.Empty">String.Empty</see>.</para>
/// </exception>
public static bool IsDirectory(string path)
{
    return PathIsDirectory(path);
}

我使用以下，它还测试扩展，这意味着它可以用于测试，如果提供的路径是一个文件，但一个文件不存在。

private static bool isDirectory(string path)
{
    bool result = true;
    System.IO.FileInfo fileTest = new System.IO.FileInfo(path);
    if (fileTest.Exists == true)
    {
        result = false;
    }
    else
    {
        if (fileTest.Extension != "")
        {
            result = false;
        }
    }
    return result;
}

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));
          }
     }
}