How to remove a single Attribute (e.g. ReadOnly) from a File?

Question

Let say, a file has the following attributes: ReadOnly, Hidden, Archived, System. How can I remove only one Attribute? (for example ReadOnly)

If I use the following, it removes all the attributes:

IO.File.SetAttributes("File.txt",IO.FileAttributes.Normal)

Satchel

read current attributes, mask the attribute you require to set, set the attribute... – Gastrolith

Answer 1

From MSDN: You can remove any attribute like this

(but @sll's answer for just ReadOnly is better for just that attribute)

using System;
using System.IO;
using System.Text;
class Test 
{
    public static void Main() 
    {
        string path = @"c:\temp\MyTest.txt";

        // Create the file if it exists.
        if (!File.Exists(path)) 
        {
            File.Create(path);
        }

        FileAttributes attributes = File.GetAttributes(path);

        if ((attributes & FileAttributes.ReadOnly) == FileAttributes.ReadOnly)
        {
            // Make the file RW
            attributes = RemoveAttribute(attributes, FileAttributes.ReadOnly);
            File.SetAttributes(path, attributes);
            Console.WriteLine("The {0} file is no longer RO.", path);
        } 
        else 
        {
            // Make the file RO
            File.SetAttributes(path, File.GetAttributes(path) | FileAttributes.Hidden);
            Console.WriteLine("The {0} file is now RO.", path);
        }
    }

    private static FileAttributes RemoveAttribute(FileAttributes attributes, FileAttributes attributesToRemove)
    {
        return attributes & ~attributesToRemove;
    }
}

Dallapiccola

What does ~ do? – Bushranger

@ newbieguy: That's the unary binary complement operator (aka bitwise not operator). learn.microsoft.com/en-us/dotnet/csharp/language-reference/… – Harber

Answer 2

Answering on your question in title regarding ReadOnly attribute:

FileInfo fileInfo = new FileInfo(pathToAFile);
fileInfo.IsReadOnly = false;

To get control over any attribute yourself you can use File.SetAttributes() method. The link also provides an example.

Neoprene

this works great! but only for ReadOnly Attribute, (I know i asked for it in the title but I also need other attributes) – Satchel

@qxxx: you are right, as I mentioned you have to use SetAttributes() method to modify another attributes – Neoprene

As a one-liner: new FileInfo(fileName) {IsReadOnly = false}.Refresh() – Monetta

Is Refresh() necessary? This example on MSDN suggests it isn't, and my code (admittedly with Mono) works if I don't call it. – Dogs

Refresh() seems not necessary for me either. – Metternich

You don't need Refresh here. IsReadOnly is setting Attributes, and setting Attributes triggers the file system change. The state of the FileInfo should be up to date, so Refresh is redundant, so I'll go ahead and remove it, if nobody minds. – Ostrogoth

Answer 3

string file = "file.txt";
FileAttributes attrs = File.GetAttributes(file);
if (attrs.HasFlag(FileAttributes.ReadOnly))
    File.SetAttributes(file, attrs & ~FileAttributes.ReadOnly);

Inferno

Answer 4

if ((oFileInfo.Attributes & FileAttributes.ReadOnly) == FileAttributes.ReadOnly)
    oFileInfo.Attributes ^= FileAttributes.ReadOnly;

Dermatome

Answer 5

For a one line solution (provided that the current user has access to change the attributes of the mentioned file) here is how I would do it:

VB.Net

Shell("attrib file.txt -r")

the negative sign means to remove and the r is for read-only. if you want to remove other attributes as well you would do:

Shell("attrib file.txt -r -s -h -a")

That will remove the Read-Only, System-File, Hidden and Archive attributes.

if you want to give back these attributes, here is how:

Shell("attrib file.txt +r +s +h +a")

the order does not matter.

C#

Process.Start("cmd.exe", "attrib file.txt +r +s +h +a");

References

• Google
• ComputerHope.com - Lots of examples and OS specific notes
• Microsoft - Page is for XP, but probably applies to later versions
• Wikipedia - Particularly the Particularities section

Heaven

These are not major content changes, they're content additions, and none of them run counter to the spirit of Stack Overflow. They're good edits, they should stay. – Jeaniejeanine

This seems like the equivalent of asking where to add a quart of oil to your car but being told you should take it to your dealership for an oil change. Why execute a shell command just to flip a file attribute bit? The answer technically works so I didn't downvote, but I did in my heart. – Emotive

@GeorgeStocker Thanks for reviewing it, I appreciate that! – Sacks

Answer 6

/// <summary>
/// Addes the given FileAttributes to the given File.
/// It's possible to combine FileAttributes: FileAttributes.Hidden | FileAttributes.ReadOnly
/// </summary>
public static void AttributesSet(this FileInfo pFile, FileAttributes pAttributes)
{
    pFile.Attributes = pFile.Attributes | pAttributes;
    pFile.Refresh();
}

/// <summary>
/// Removes the given FileAttributes from the given File.
/// It's possible to combine FileAttributes: FileAttributes.Hidden | FileAttributes.ReadOnly
/// </summary>
public static void AttributesRemove(this FileInfo pFile, FileAttributes pAttributes)
{
    pFile.Attributes = pFile.Attributes & ~pAttributes;
    pFile.Refresh();
}

/// <summary>
/// Checks the given File on the given Attributes.
/// It's possible to combine FileAttributes: FileAttributes.Hidden | FileAttributes.ReadOnly
/// </summary>
/// <returns>True if any Attribute is set, False if non is set</returns>
public static bool AttributesIsAnySet(this FileInfo pFile, FileAttributes pAttributes)
{
    return ((pFile.Attributes & pAttributes) > 0);
}

/// <summary>
/// Checks the given File on the given Attributes.
/// It's possible to combine FileAttributes: FileAttributes.Hidden | FileAttributes.ReadOnly
/// </summary>
/// <returns>True if all Attributes are set, False if any is not set</returns>
public static bool AttributesIsSet(this FileInfo pFile, FileAttributes pAttributes)
{
    return (pAttributes == (pFile.Attributes & pAttributes));
}

Example:

private static void Test()
{
    var lFileInfo = new FileInfo(@"C:\Neues Textdokument.txt");
    lFileInfo.AttributesSet(FileAttributes.Hidden | FileAttributes.ReadOnly);
    lFileInfo.AttributesSet(FileAttributes.Temporary);
    var lBool1 = lFileInfo.AttributesIsSet(FileAttributes.Hidden);
    var lBool2 = lFileInfo.AttributesIsSet(FileAttributes.Temporary);
    var lBool3 = lFileInfo.AttributesIsSet(FileAttributes.Encrypted);
    var lBool4 = lFileInfo.AttributesIsSet(FileAttributes.ReadOnly | FileAttributes.Temporary);
    var lBool5 = lFileInfo.AttributesIsSet(FileAttributes.ReadOnly | FileAttributes.Encrypted);
    var lBool6 = lFileInfo.AttributesIsAnySet(FileAttributes.ReadOnly | FileAttributes.Temporary);
    var lBool7 = lFileInfo.AttributesIsAnySet(FileAttributes.ReadOnly | FileAttributes.Encrypted);
    var lBool8 = lFileInfo.AttributesIsAnySet(FileAttributes.Encrypted);
    lFileInfo.AttributesRemove(FileAttributes.Temporary);
    lFileInfo.AttributesRemove(FileAttributes.Hidden | FileAttributes.ReadOnly);
}

Metritis

Answer 7

Lots of code in these examples, if you want a simple solution(without Shell):

File.SetAttributes(filepath, ~FileAttributes.ReadOnly & File.GetAttributes(filepath));

Chervonets

Answer 8

Use this:

private static FileAttributes RemoveAttribute(FileAttributes attributes, FileAttributes attributesToRemove)

Read detail here in MSDN: http://msdn.microsoft.com/en-us/library/system.io.file.setattributes.aspx

Warrenwarrener