我尝试过的每一个方法都会在某个时候失败，并出现System.IO错误。即使文件夹为空或非空、只读或非只读等，以下方法也能正常工作。

ProcessStartInfo Info = new ProcessStartInfo();  
Info.Arguments = "/C rd /s /q \"C:\\MyFolder"";  
Info.WindowStyle = ProcessWindowStyle.Hidden;  
Info.CreateNoWindow = true;  
Info.FileName = "cmd.exe";  
Process.Start(Info); 

我们也可以表现出对LINQ的热爱：

using System.IO;
using System.Linq;
…
var directory = Directory.GetParent(TestContext.TestDir);

directory.EnumerateFiles()
    .ToList().ForEach(f => f.Delete());

directory.EnumerateDirectories()
    .ToList().ForEach(d => d.Delete(true));

请注意，我这里的解决方案不是高性能的，因为我使用的是Get*（）.ToList（）.ForEach（…），它两次生成相同的IEnumerable。我使用扩展方法来避免此问题：

using System.IO;
using System.Linq;
…
var directory = Directory.GetParent(TestContext.TestDir);

directory.EnumerateFiles()
    .ForEachInEnumerable(f => f.Delete());

directory.EnumerateDirectories()
    .ForEachInEnumerable(d => d.Delete(true));

这是扩展方法：

/// <summary>
/// Extensions for <see cref="System.Collections.Generic.IEnumerable"/>.
/// </summary>
public static class IEnumerableOfTExtensions
{
    /// <summary>
    /// Performs the <see cref="System.Action"/>
    /// on each item in the enumerable object.
    /// </summary>
    /// <typeparam name="TEnumerable">The type of the enumerable.</typeparam>
    /// <param name="enumerable">The enumerable.</param>
    /// <param name="action">The action.</param>
    /// <remarks>
    /// “I am philosophically opposed to providing such a method, for two reasons.
    /// …The first reason is that doing so violates the functional programming principles
    /// that all the other sequence operators are based upon. Clearly the sole purpose of a call
    /// to this method is to cause side effects.”
    /// —Eric Lippert, “foreach” vs “ForEach” [http://blogs.msdn.com/b/ericlippert/archive/2009/05/18/foreach-vs-foreach.aspx]
    /// </remarks>
    public static void ForEachInEnumerable<TEnumerable>(this IEnumerable<TEnumerable> enumerable, Action<TEnumerable> action)
    {
        foreach (var item in enumerable)
        {
            action(item);
        }
    }
}

在我的情况下

var PhotoFile = _context.Records.Where(x => id_or_ids.Contains(x.Id)).Select(x => x.Photo).ToList();

            System.IO.DirectoryInfo di = new DirectoryInfo("wwwroot/uploads");

            foreach (FileInfo file in di.GetFiles())
            {
                if (PhotoFile.IndexOf(file.Name) != -1)
                {
                    file.Delete();
                }
            }

以下代码将递归清除文件夹：

private void clearFolder(string FolderName)
{
    DirectoryInfo dir = new DirectoryInfo(FolderName);

    foreach(FileInfo fi in dir.GetFiles())
    {
        fi.Delete();
    }

    foreach (DirectoryInfo di in dir.GetDirectories())
    {
        clearFolder(di.FullName);
        di.Delete();
    }
}

使用DirectoryInfo的GetDirectories方法。

foreach (DirectoryInfo subDir in new DirectoryInfo(targetDir).GetDirectories())
                    subDir.Delete(true);

private void ClearDirectory(string path)
{
    if (Directory.Exists(path))//if folder exists
    {
        Directory.Delete(path, true);//recursive delete (all subdirs, files)
    }
    Directory.CreateDirectory(path);//creates empty directory
}