How can I obtain the case-sensitive path on Windows?

Question

I need to know which is the real path of a given path.

For example:

The real path is: d:\\src\\File.txt
And the user give me: D:\\src\\file.txt
I nee

Answer 1

As Borja's answer does not work for volumes where 8.3 names are disabled, here the recursive implementation that Tergiver suggests (works for files and folders, as well as the files and folders of UNC shares but not on their machine names nor their share names).

Non-existing file or folders are no problem, what exists is verified and corrected, but you might run into folder-redirection issues, e.g when trying to get the correct path of "C:\WinDoWs\sYsteM32\driVErs\eTC\Hosts" you'll get "C:\Windows\System32\drivers\eTC\hosts" on a 64bit windows as there is no "etc" folder withing "C:\Windows\sysWOW64\drivers".

Test Scenario:

        Directory.CreateDirectory(@"C:\Temp\SomeFolder");
        File.WriteAllLines(@"C:\Temp\SomeFolder\MyTextFile.txt", new String[] { "Line1", "Line2" });

Usage:

        FileInfo myInfo = new FileInfo(@"C:\TEMP\SOMEfolder\MyTeXtFiLe.TxT");
        String myResult = myInfo.GetFullNameWithCorrectCase(); //Returns "C:\Temp\SomeFolder\MyTextFile.txt"

Code:

public static class FileSystemInfoExt {

    public static String GetFullNameWithCorrectCase(this FileSystemInfo fileOrFolder) {
        //Check whether null to simulate instance method behavior
        if (Object.ReferenceEquals(fileOrFolder, null)) throw new NullReferenceException();
        //Initialize common variables
        String myResult = GetCorrectCaseOfParentFolder(fileOrFolder.FullName);
        return myResult;
    }

    private static String GetCorrectCaseOfParentFolder(String fileOrFolder) {
        String myParentFolder = Path.GetDirectoryName(fileOrFolder);
        String myChildName = Path.GetFileName(fileOrFolder);
        if (Object.ReferenceEquals(myParentFolder, null)) return fileOrFolder.TrimEnd(new char[]{Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar });
        if (Directory.Exists(myParentFolder)) {
            //myParentFolder = GetLongPathName.Invoke(myFullName);
            String myFileOrFolder = Directory.GetFileSystemEntries(myParentFolder, myChildName).FirstOrDefault();
            if (!Object.ReferenceEquals(myFileOrFolder, null)) {
                myChildName = Path.GetFileName(myFileOrFolder);
            }
        }
        return GetCorrectCaseOfParentFolder(myParentFolder) + Path.DirectorySeparatorChar + myChildName;
    }

}

Answer 2

I tried to avoid dll imports so the best way for me was to use System.Linq and the System.IO.Directory class.

For your example Real path is: d:\src\File.txt The user give me: D:\src\file.txt

Code for this:

using System.Linq;

public static class PathUtils
{
    public static string RealPath(string inputPath)
    {
        return Directory.GetFiles(Path.GetDirectoryName(inputPath))
            .FirstOrDefault(p => String.Equals(Path.GetFileName(p), 
                Path.GetFileName(inputPath), StringComparison.OrdinalIgnoreCase));
    }
}

var p = PathUtils.RealPath(@"D:\src\file.txt");

Method should return the path "d:\src\File.txt" or "D:\src\File.txt".