我正在处理一个目录和文件的 TreeView。用户可以选择文件或目录，然后对其执行某些操作。这需要我编写一个方法，根据用户的选择执行不同的操作。
目前我正在做类似于下面的事情来确定路径是文件还是目录：
bool bIsFile = false;
bool bIsDirectory = false;
try
{
string[] subfolders = Directory.GetDirectories(strFilePath);
bIsDirectory = true;
bIsFile = false;
}
catch(System.IO.IOException)
{
bIsFolder = false;
bIsFile = true;
}
我感觉一定有更好的方法！我希望能够找到标准的 .NET 方法来处理这个问题，但我没有找到。是否存在这样的方法？如果不存在，最直接的方法是确定一个路径是文件还是目录？
// get the file attributes for file or directory
FileAttributes attr = File.GetAttributes(@"c:\Temp");
//detect whether its a directory or file
if ((attr & FileAttributes.Directory) == FileAttributes.Directory)
MessageBox.Show("Its a directory");
else
MessageBox.Show("Its a file");
根据下面的评论，如果你使用的是 .NET 4.0 或更高版本（且最大性能不是关键问题），你可以以更整洁的方式编写代码：
// get the file attributes for file or directory
FileAttributes attr = File.GetAttributes(@"c:\Temp");
if (attr.HasFlag(FileAttributes.Directory))
MessageBox.Show("Its a directory");
else
MessageBox.Show("Its a file");
&运算符将返回一个二进制值，其中仅打开了两个操作数中都打开（1）的位。在这种情况下，对 attr 和 FileAttributes.Directory 值执行按位与操作将返回 FileAttributes.Directory 的值，如果目录文件属性位被打开的话。请参阅 http://en.wikipedia.org/wiki/Bitwise_operation 以获取更好的解释。 - Kyle Traubermanattr.HasFlag(FileAttributes.Directory) 替代。 - Şafak Gür/// 如果路径是目录则返回 true，如果是文件则返回 false，如果既不是也不存在则返回 null。 public static bool? IsDirFile(this string path) { bool? result = null; if(Directory.Exists(path) || File.Exists(path)) { // 获取文件或目录的文件属性 var fileAttr = File.GetAttributes(path); if (fileAttr.HasFlag(FileAttributes.Directory)) result = true; else result = false; } return result; } - Michael Socha试试这个怎么样？
if(File.Exists(data.path))
{
// is file
}
else if(Directory.Exists(data.path))
{
// is Folder
}
else
{
// invalid path
}
即使目录存在，如果它不是文件，File.Exists()将返回false，所以如果其返回true，则说明我们得到了一个文件；如果返回false，则可能是一个目录或无效路径，因此我们接下来使用Directory.Exists()测试其是否为有效目录，如果返回true，则说明我们有一个目录，否则就是无效路径。
File.GetAttributes() 不同，这还有一个好处，就是在路径无效时不会抛出异常。 - Deannapublic static bool? IsDirectory(string path){
if (Directory.Exists(path))
return true; // 是一个文件夹
else if (File.Exists(path))
return false; // 是一个文件
else
return null; // 不存在
} - Dustin Townsend只需这一行代码，就可以确定路径是目录还是文件：
File.GetAttributes(data.Path).HasFlag(FileAttributes.Directory)
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));
}
这与其他人的答案相似，但并不完全相同。
Path.DirectorySeparatorChar 和 Path.AltDirectorySeparatorChar。 - drzaus在结合其他回答的建议后，我意识到我想到的与Ronnie Overby's answer大致相同。以下是一些测试，以指出需要考虑的一些事情：
C:\Temp\folder_with.dotPath.DirectorySeparatorChar和Path.AltDirectorySeparatorChar）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);
}
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
/// <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://dev59.com/wHM_5IYBdhLWcg3wZSPX
// turns out to be about the same as https://dev59.com/wHM_5IYBdhLWcg3wZSPX#19596821
// 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;
}
Path.DirectorySeparatorChar.ToString()代替字符串连接符""？ - iCollect.it Ltdnew String(Path.DirectorySeparatorChar, 1)，因为这就是 ToString 所做的。 - drzausprivate static bool IsDirectory(string path)
{
System.IO.FileAttributes fa = System.IO.File.GetAttributes(path);
return (fa & FileAttributes.Directory) != 0;
}
当填充TreeView控件时，您可以考虑向其标签属性添加对象，其中包含有关该项的其他元数据。例如，您可以为文件添加FileInfo对象，为目录添加DirectoryInfo对象，然后在标记属性中测试项目类型，以避免在单击项目时进行额外的系统调用来获取该数据。
isDirectory = (fa & FileAttributes.Directory) != 0);。 - Immortal Blue考虑到Exists和Attributes属性的行为，以下是我能想到的最好方法：
using System.IO;
public static class FileSystemInfoExtensions
{
/// <summary>
/// Checks whether a FileInfo or DirectoryInfo object is a directory, or intended to be a directory.
/// </summary>
/// <param name="fileSystemInfo"></param>
/// <returns></returns>
public static bool IsDirectory(this FileSystemInfo fileSystemInfo)
{
if (fileSystemInfo == null)
{
return false;
}
if ((int)fileSystemInfo.Attributes != -1)
{
// if attributes are initialized check the directory flag
return fileSystemInfo.Attributes.HasFlag(FileAttributes.Directory);
}
// If we get here the file probably doesn't exist yet. The best we can do is
// try to judge intent. Because directories can have extensions and files
// can lack them, we can't rely on filename.
//
// We can reasonably assume that if the path doesn't exist yet and
// FileSystemInfo is a DirectoryInfo, a directory is intended. FileInfo can
// make a directory, but it would be a bizarre code path.
return fileSystemInfo is DirectoryInfo;
}
}
以下是测试结果：
[TestMethod]
public void IsDirectoryTest()
{
// non-existing file, FileAttributes not conclusive, rely on type of FileSystemInfo
const string nonExistentFile = @"C:\TotallyFakeFile.exe";
var nonExistentFileDirectoryInfo = new DirectoryInfo(nonExistentFile);
Assert.IsTrue(nonExistentFileDirectoryInfo.IsDirectory());
var nonExistentFileFileInfo = new FileInfo(nonExistentFile);
Assert.IsFalse(nonExistentFileFileInfo.IsDirectory());
// non-existing directory, FileAttributes not conclusive, rely on type of FileSystemInfo
const string nonExistentDirectory = @"C:\FakeDirectory";
var nonExistentDirectoryInfo = new DirectoryInfo(nonExistentDirectory);
Assert.IsTrue(nonExistentDirectoryInfo.IsDirectory());
var nonExistentFileInfo = new FileInfo(nonExistentDirectory);
Assert.IsFalse(nonExistentFileInfo.IsDirectory());
// Existing, rely on FileAttributes
const string existingDirectory = @"C:\Windows";
var existingDirectoryInfo = new DirectoryInfo(existingDirectory);
Assert.IsTrue(existingDirectoryInfo.IsDirectory());
var existingDirectoryFileInfo = new FileInfo(existingDirectory);
Assert.IsTrue(existingDirectoryFileInfo.IsDirectory());
// Existing, rely on FileAttributes
const string existingFile = @"C:\Windows\notepad.exe";
var existingFileDirectoryInfo = new DirectoryInfo(existingFile);
Assert.IsFalse(existingFileDirectoryInfo.IsDirectory());
var existingFileFileInfo = new FileInfo(existingFile);
Assert.IsFalse(existingFileFileInfo.IsDirectory());
}
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。这样做可以避免在提供可能的存在失败冗余的同时，出现文件属性错误。
[DllImport(SHLWAPI, CharSet = CharSet.Unicode)]
[return: MarshalAsAttribute(UnmanagedType.Bool)]
[ResourceExposure(ResourceScope.None)]
internal static extern bool PathIsDirectory([MarshalAsAttribute(UnmanagedType.LPWStr), In] string pszPath);
#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);
}
以下是我们使用的技术：
using System;
using System.IO;
namespace crmachine.CommonClasses
{
public static class CRMPath
{
public static bool IsDirectory(string path)
{
if (path == null)
{
throw new ArgumentNullException("path");
}
string reason;
if (!IsValidPathString(path, out reason))
{
throw new ArgumentException(reason);
}
if (!(Directory.Exists(path) || File.Exists(path)))
{
throw new InvalidOperationException(string.Format("Could not find a part of the path '{0}'",path));
}
return (new System.IO.FileInfo(path).Attributes & FileAttributes.Directory) == FileAttributes.Directory;
}
public static bool IsValidPathString(string pathStringToTest, out string reasonForError)
{
reasonForError = "";
if (string.IsNullOrWhiteSpace(pathStringToTest))
{
reasonForError = "Path is Null or Whitespace.";
return false;
}
if (pathStringToTest.Length > CRMConst.MAXPATH) // MAXPATH == 260
{
reasonForError = "Length of path exceeds MAXPATH.";
return false;
}
if (PathContainsInvalidCharacters(pathStringToTest))
{
reasonForError = "Path contains invalid path characters.";
return false;
}
if (pathStringToTest == ":")
{
reasonForError = "Path consists of only a volume designator.";
return false;
}
if (pathStringToTest[0] == ':')
{
reasonForError = "Path begins with a volume designator.";
return false;
}
if (pathStringToTest.Contains(":") && pathStringToTest.IndexOf(':') != 1)
{
reasonForError = "Path contains a volume designator that is not part of a drive label.";
return false;
}
return true;
}
public static bool PathContainsInvalidCharacters(string path)
{
if (path == null)
{
throw new ArgumentNullException("path");
}
bool containedInvalidCharacters = false;
for (int i = 0; i < path.Length; i++)
{
int n = path[i];
if (
(n == 0x22) || // "
(n == 0x3c) || // <
(n == 0x3e) || // >
(n == 0x7c) || // |
(n < 0x20) // the control characters
)
{
containedInvalidCharacters = true;
}
}
return containedInvalidCharacters;
}
public static bool FilenameContainsInvalidCharacters(string filename)
{
if (filename == null)
{
throw new ArgumentNullException("filename");
}
bool containedInvalidCharacters = false;
for (int i = 0; i < filename.Length; i++)
{
int n = filename[i];
if (
(n == 0x22) || // "
(n == 0x3c) || // <
(n == 0x3e) || // >
(n == 0x7c) || // |
(n == 0x3a) || // :
(n == 0x2a) || // *
(n == 0x3f) || // ?
(n == 0x5c) || // \
(n == 0x2f) || // /
(n < 0x20) // the control characters
)
{
containedInvalidCharacters = true;
}
}
return containedInvalidCharacters;
}
}
}