我想知道如何确定字符串是否是有效的文件路径。
文件路径可能或可能不。
答案 0 :(得分：51)
您可以使用FileInfo构造函数。如果“文件名为空，仅包含空格或包含无效字符”，它将抛出ArgumentException。它也可以抛出SecurityException或UnauthorizedAccessException，如果你只关心格式，我认为你可以忽略它。
另一种选择是直接与Path.GetInvalidPathChars核对。 E.g：
boolean possiblePath = pathString.IndexOfAny(Path.GetInvalidPathChars()) == -1;
答案 1 :(得分：21)
100％准确地检查路径的字符串格式非常困难，因为它取决于使用它的文件系统（如果不在同一台计算机上，则取决于网络协议）。
即使在Windows甚至NTFS中，它也不简单，因为它依赖于.NET .NET在后台使用以与内核通信。
由于目前大多数文件系统都支持unicode，因此可能还需要检查所有规则以进行正确编码的unicode，规范化等等。
我要做的只是进行一些基本检查，然后在使用路径后正确处理异常。有关可能的规则，请参阅：
答案 2 :(得分：8)
以下是您可能会使用的一些内容：
Path.IsPathRooted查看它是否不是相对路径，然后使用来自{的驱动器{1}}查看您的路径是否包含其中一个有效的驱动器。Environment.GetLogicalDrives()和Path.GetInvalidFileNameChars()，它们不会完全重叠。您还可以将Path.GetInvalidPathChars()和Path.GetDirectoryName(path)与您的输入名称一起使用，throw an exception如果path参数包含无效字符，为空或仅包含空格。
答案 3 :(得分：3)
在尝试创建该文件之前，您无法确定。也许路径有效但安全设置不允许创建文件。可以告诉你路径是否真的有效的唯一实例是OS，所以为什么不尝试创建该文件捕获IOException，这表明出现了什么问题？ Imho这是一种更简单的方法：假设输入是有效的，如果不是，则做一些事情，而不是做很多不必要的工作。
答案 4 :(得分：2)
你试过正则表达式吗？
^([a-zA-Z]\:)(\\[^\\/:*?<>"|]*(?<![ ]))*(\.[a-zA-Z]{2,6})$
应该有效
答案 5 :(得分：2)
尝试使用此方法，尝试涵盖所有可能的异常方案。它适用于几乎所有与Windows相关的路径。
/// <summary>
/// Validate the Path. If path is relative append the path to the project directory by default.
/// </summary>
/// <param name="path">Path to validate</param>
/// <param name="RelativePath">Relative path</param>
/// <param name="Extension">If want to check for File Path</param>
/// <returns></returns>
private static bool ValidateDllPath(ref string path, string RelativePath = "", string Extension = "")
{
// Check if it contains any Invalid Characters.
if (path.IndexOfAny(Path.GetInvalidPathChars()) == -1)
{
try
{
// If path is relative take %IGXLROOT% as the base directory
if (!Path.IsPathRooted(path))
{
if (string.IsNullOrEmpty(RelativePath))
{
// Exceptions handled by Path.GetFullPath
// ArgumentException path is a zero-length string, contains only white space, or contains one or more of the invalid characters defined in GetInvalidPathChars. -or- The system could not retrieve the absolute path.
//
// SecurityException The caller does not have the required permissions.
//
// ArgumentNullException path is null.
//
// NotSupportedException path contains a colon (":") that is not part of a volume identifier (for example, "c:\").
// PathTooLongException The specified path, file name, or both exceed the system-defined maximum length. For example, on Windows-based platforms, paths must be less than 248 characters, and file names must be less than 260 characters.
// RelativePath is not passed so we would take the project path
path = Path.GetFullPath(RelativePath);
}
else
{
// Make sure the path is relative to the RelativePath and not our project directory
path = Path.Combine(RelativePath, path);
}
}
// Exceptions from FileInfo Constructor:
// System.ArgumentNullException:
// fileName is null.
//
// System.Security.SecurityException:
// The caller does not have the required permission.
//
// System.ArgumentException:
// The file name is empty, contains only white spaces, or contains invalid characters.
//
// System.IO.PathTooLongException:
// The specified path, file name, or both exceed the system-defined maximum
// length. For example, on Windows-based platforms, paths must be less than
// 248 characters, and file names must be less than 260 characters.
//
// System.NotSupportedException:
// fileName contains a colon (:) in the middle of the string.
FileInfo fileInfo = new FileInfo(path);
// Exceptions using FileInfo.Length:
// System.IO.IOException:
// System.IO.FileSystemInfo.Refresh() cannot update the state of the file or
// directory.
//
// System.IO.FileNotFoundException:
// The file does not exist.-or- The Length property is called for a directory.
bool throwEx = fileInfo.Length == -1;
// Exceptions using FileInfo.IsReadOnly:
// System.UnauthorizedAccessException:
// Access to fileName is denied.
// The file described by the current System.IO.FileInfo object is read-only.-or-
// This operation is not supported on the current platform.-or- The caller does
// not have the required permission.
throwEx = fileInfo.IsReadOnly;
if (!string.IsNullOrEmpty(Extension))
{
// Validate the Extension of the file.
if (Path.GetExtension(path).Equals(Extension, StringComparison.InvariantCultureIgnoreCase))
{
// Trim the Library Path
path = path.Trim();
return true;
}
else
{
return false;
}
}
else
{
return true;
}
}
catch (ArgumentNullException)
{
// System.ArgumentNullException:
// fileName is null.
}
catch (System.Security.SecurityException)
{
// System.Security.SecurityException:
// The caller does not have the required permission.
}
catch (ArgumentException)
{
// System.ArgumentException:
// The file name is empty, contains only white spaces, or contains invalid characters.
}
catch (UnauthorizedAccessException)
{
// System.UnauthorizedAccessException:
// Access to fileName is denied.
}
catch (PathTooLongException)
{
// System.IO.PathTooLongException:
// The specified path, file name, or both exceed the system-defined maximum
// length. For example, on Windows-based platforms, paths must be less than
// 248 characters, and file names must be less than 260 characters.
}
catch (NotSupportedException)
{
// System.NotSupportedException:
// fileName contains a colon (:) in the middle of the string.
}
catch (FileNotFoundException)
{
// System.FileNotFoundException
// The exception that is thrown when an attempt to access a file that does not
// exist on disk fails.
}
catch (IOException)
{
// System.IO.IOException:
// An I/O error occurred while opening the file.
}
catch (Exception)
{
// Unknown Exception. Might be due to wrong case or nulll checks.
}
}
else
{
// Path contains invalid characters
}
return false;
}
答案 6 :(得分：1)
Regex driveCheck = new Regex(@"^[a-zA-Z]:\\$");
if (string.IsNullOrWhiteSpace(path) || path.Length < 3)
{
return false;
}
if (!driveCheck.IsMatch(path.Substring(0, 3)))
{
return false;
}
string strTheseAreInvalidFileNameChars = new string(Path.GetInvalidPathChars());
strTheseAreInvalidFileNameChars += @":/?*" + "\"";
Regex containsABadCharacter = new Regex("[" + Regex.Escape(strTheseAreInvalidFileNameChars) + "]");
if (containsABadCharacter.IsMatch(path.Substring(3, path.Length - 3)))
{
return false;
}
DirectoryInfo directoryInfo = new DirectoryInfo(Path.GetFullPath(path));
try
{
if (!directoryInfo.Exists)
{
directoryInfo.Create();
}
}
catch (Exception ex)
{
if (Log.IsErrorEnabled)
{
Log.Error(ex.Message);
}
return false;
}`enter code here`
return true;
}
答案 7 :(得分：0)
我在Dmitry Borysov的regexlib.com（http://regexlib.com/REDetails.aspx?regexp_id=345）找到了这个。
“文件名验证器。验证UNC（\ server \ share \ file）和常规MS路径（c：\ file）”
^(([a-zA-Z]:|\\)\\)?(((\.)|(\.\.)|([^\\/:\*\?"\|<>\. ](([^\\/:\*\?"\|<>\. ])|([^\\/:\*\?"\|<>]*[^\\/:\*\?"\|<>\. ]))?))\\)*[^\\/:\*\?"\|<>\. ](([^\\/:\*\?"\|<>\. ])|([^\\/:\*\?"\|<>]*[^\\/:\*\?"\|<>\. ]))?$
使用Regex.IsMatch运行它，你会得到一个bool，表明它是否有效。我认为正则表达式是可行的，因为该文件可能不存在。
答案 8 :(得分：0)
静态类System.IO.Path可以做你想要的。
答案 9 :(得分：0)
您可以在try catch语句中使用Path.Combine（）：
string path = @" your path ";
try
{
Path.Combine(path);
}
catch
{
MessageBox.Show("Invalid path");
}
修改 请注意，如果path包含通配符（'*'和'？'），则此函数不会引发异常，因为它们可以在搜索字符串中使用。