问题
What is an easy way to check if directory 1 is a subdirectory of directory 2 and vice versa?
I checked the Path and DirectoryInfo helperclasses but found no system-ready function for this. I thought it would be in there somewhere.
Do you guys have an idea where to find this?
I tried writing a check myself, but it's more complicated than I had anticipated when I started.
回答1:
You can compare directory2 to directory1's Parent property when using a DirectoryInfo in both cases.
DirectoryInfo d1 = new DirectoryInfo(@"C:\Program Files\MyApp");
DirectoryInfo d2 = new DirectoryInfo(@"C:\Program Files\MyApp\Images");
if(d2.Parent.FullName == d1.FullName)
{
Console.WriteLine ("Sub directory");
}
回答2:
In response to the first part of the question: "Is dir1 a sub-directory of dir2?", this code should work:
public bool IsSubfolder(string parentPath, string childPath)
{
var parentUri = new Uri(parentPath);
var childUri = new DirectoryInfo(childPath).Parent;
while (childUri != null)
{
if(new Uri(childUri.FullName) == parentUri)
{
return true;
}
childUri = childUri.Parent;
}
return false;
}
The URIs (on Windows at least, might be different on Mono/Linux) are case-insensitive. If case sensitivity is important, use the Compare method on Uri instead.
回答3:
Here's a simpler way to do it using the Uri class:
var parentUri = new Uri(parentPath);
var childUri = new Uri(childPath);
if (parentUri != childUri && parentUri.IsBaseOf(childUri))
{
//dowork
}
回答4:
See original answer here: https://stackoverflow.com/a/31941159/134761
- Case insensitive
- Tolerates mix of
\and/folder delimiters - Tolerates
..\in path - Avoids matching on partial folder names (
c:\foobarnot a subpath ofc:\foo)
Code:
public static class StringExtensions
{
/// <summary>
/// Returns true if <paramref name="path"/> starts with the path <paramref name="baseDirPath"/>.
/// The comparison is case-insensitive, handles / and \ slashes as folder separators and
/// only matches if the base dir folder name is matched exactly ("c:\foobar\file.txt" is not a sub path of "c:\foo").
/// </summary>
public static bool IsSubPathOf(this string path, string baseDirPath)
{
string normalizedPath = Path.GetFullPath(path.Replace('/', '\\')
.WithEnding("\\"));
string normalizedBaseDirPath = Path.GetFullPath(baseDirPath.Replace('/', '\\')
.WithEnding("\\"));
return normalizedPath.StartsWith(normalizedBaseDirPath, StringComparison.OrdinalIgnoreCase);
}
/// <summary>
/// Returns <paramref name="str"/> with the minimal concatenation of <paramref name="ending"/> (starting from end) that
/// results in satisfying .EndsWith(ending).
/// </summary>
/// <example>"hel".WithEnding("llo") returns "hello", which is the result of "hel" + "lo".</example>
public static string WithEnding([CanBeNull] this string str, string ending)
{
if (str == null)
return ending;
string result = str;
// Right() is 1-indexed, so include these cases
// * Append no characters
// * Append up to N characters, where N is ending length
for (int i = 0; i <= ending.Length; i++)
{
string tmp = result + ending.Right(i);
if (tmp.EndsWith(ending))
return tmp;
}
return result;
}
/// <summary>Gets the rightmost <paramref name="length" /> characters from a string.</summary>
/// <param name="value">The string to retrieve the substring from.</param>
/// <param name="length">The number of characters to retrieve.</param>
/// <returns>The substring.</returns>
public static string Right([NotNull] this string value, int length)
{
if (value == null)
{
throw new ArgumentNullException("value");
}
if (length < 0)
{
throw new ArgumentOutOfRangeException("length", length, "Length is less than zero");
}
return (length < value.Length) ? value.Substring(value.Length - length) : value;
}
}
Test cases (NUnit):
[TestFixture]
public class StringExtensionsTest
{
[TestCase(@"c:\foo", @"c:", Result = true)]
[TestCase(@"c:\foo", @"c:\", Result = true)]
[TestCase(@"c:\foo", @"c:\foo", Result = true)]
[TestCase(@"c:\foo", @"c:\foo\", Result = true)]
[TestCase(@"c:\foo\", @"c:\foo", Result = true)]
[TestCase(@"c:\foo\bar\", @"c:\foo\", Result = true)]
[TestCase(@"c:\foo\bar", @"c:\foo\", Result = true)]
[TestCase(@"c:\foo\a.txt", @"c:\foo", Result = true)]
[TestCase(@"c:\FOO\a.txt", @"c:\foo", Result = true)]
[TestCase(@"c:/foo/a.txt", @"c:\foo", Result = true)]
[TestCase(@"c:\foobar", @"c:\foo", Result = false)]
[TestCase(@"c:\foobar\a.txt", @"c:\foo", Result = false)]
[TestCase(@"c:\foobar\a.txt", @"c:\foo\", Result = false)]
[TestCase(@"c:\foo\a.txt", @"c:\foobar", Result = false)]
[TestCase(@"c:\foo\a.txt", @"c:\foobar\", Result = false)]
[TestCase(@"c:\foo\..\bar\baz", @"c:\foo", Result = false)]
[TestCase(@"c:\foo\..\bar\baz", @"c:\bar", Result = true)]
[TestCase(@"c:\foo\..\bar\baz", @"c:\barr", Result = false)]
public bool IsSubPathOfTest(string path, string baseDirPath)
{
return path.IsSubPathOf(baseDirPath);
}
}
Update 2015-08-18: Fix bug matching on partial folder names. Add test cases.
Update 2016-01-29: Link to original question https://stackoverflow.com/a/31941159/134761
回答5:
DirectoryInfo has a property Parent which is also a DirectoryInfo type. You can use that to to determine if your directory is a subdirectory of a parent directory.
回答6:
The second directories(d2) full name will contain the full name of the first directory(d1) if it is a sub-folder of d1.
This assumes that you are using valid directories
if (d2.FullName.Contains(d1.FullName))
{
//dowork
}
If you need to check for mapped drives you could try
static void Main(string[] args)
{
if (GetUNCPath(d2.FullName).ToLower().Contains(GetUNCPath(d1.FullName).ToLower()))
{
}
}
[DllImport("mpr.dll", CharSet = CharSet.Unicode, SetLastError = true)]
private static extern int WNetGetConnection(
[MarshalAs(UnmanagedType.LPTStr)] string localName,
[MarshalAs(UnmanagedType.LPTStr)] StringBuilder remoteName, ref int length);
private static string GetUNCPath(string originalPath)
{
StringBuilder sb = new StringBuilder(512);
int size = sb.Capacity;
// look for the {LETTER}: combination ...
if (originalPath.Length > 2 && originalPath[1] == ':')
{
// don't use char.IsLetter here - as that can be misleading
// the only valid drive letters are a-z && A-Z.
char c = originalPath[0];
if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z'))
{
int error = WNetGetConnection(originalPath.Substring(0, 2), sb, ref size);
if (error == 0)
{
DirectoryInfo dir = new DirectoryInfo(originalPath);
string path = Path.GetFullPath(originalPath).Substring(Path.GetPathRoot(originalPath).Length);
return Path.Combine(sb.ToString().TrimEnd(), path);
}
}
}
return originalPath;
}
Code for mapped drive taken from http://social.msdn.microsoft.com/Forums/en/csharpgeneral/thread/6f79f2b3-d092-431f-bc28-d15d93cf5d09
回答7:
If you have two path then look at this:
Normalize directory names in C#
http://filedirectorypath.codeplex.com/ (I don't know the quality of it)
And use this:
var ancestor = new DirectoryPathAbsolute(ancestorPath);
var child = new DirectoryPathAbsolute(childPath);
var res = child.IsChildDirectoryOf(ancestor); //I don't think it actually checks for case-sensitive filesystems
Otherwise, if you want to know whether a directory exists as a subdirectory in a path take a look on:
Directory.EnumerateDirectories
Came in .Net 4.0. Example:
Does path contain a directory starting with Console:
//* is a wildcard. If you remove it, it search for directories called "Console"
var res = Directory.EnumerateDirectories(@path, "Console*", SearchOption.AllDirectories).Any();
回答8:
You can use Path.GetDirectoryName Method to get parent directory. It works for directories too.
回答9:
public static bool IsSubfolder(DirectoryInfo parentPath, DirectoryInfo childPath)
{
return parentPath.FullName.StartsWith(childPath.FullName+Path.DirectorySeparatorChar);
}
回答10:
this is what I got, after first verifying that the two directory path strings are something and in a path format I know something about: shouldnotbechilddirpath.ToUpper().StartsWith(maybeparentdirpath.ToUpper())
Be sure to take out the ToUppers() if you are maybe working in a case sensitive file system.
来源：https://stackoverflow.com/questions/3525775/how-to-check-if-directory-1-is-a-subdirectory-of-dir2-and-vice-versa