FileInfo.IsReadOnly Property

Definition

Namespace:

System.IO

Assembly:

System.Runtime.dll

Source:

FileInfo.cs

Gets or sets a value that determines if the current file is read only.

public:
 property bool IsReadOnly { bool get(); void set(bool value); };

public bool IsReadOnly { get; set; }

member this.IsReadOnly : bool with get, set

Public Property IsReadOnly As Boolean

Property Value

Boolean

true if the current file is read only or could not be found; otherwise, false.

Exceptions

FileNotFoundException

The file described by the current FileInfo object could not be found when trying to set the IsReadOnly property. (Note that getting this property for a nonexistent file will not throw an exception, but rather returns true.)

IOException

An I/O error occurred while opening the file.

UnauthorizedAccessException

This operation is not supported on the current platform.

-or-

The caller does not have the required permission.

ArgumentException

The user does not have write permission, but attempted to set this property to false.

Examples

The following example creates a temporary file, uses the IsReadOnly property to first check and then set its read-only status, and finally marks it as read-write in order to delete it.

using namespace System;
using namespace System::IO;

int main()
{
    // Create a temporary file.
    String^ filePath = Path::GetTempFileName();
    Console::WriteLine("Created a temp file at '{0}.", filePath);

    // Create a new FileInfo object.
    FileInfo^ fInfo = gcnew FileInfo(filePath);
    
    // Get the read-only value for a file.
    bool isReadOnly = fInfo->IsReadOnly;

    // Display whether the file is read-only.
    Console::WriteLine("The file read-only value for '{0}' is {1}.", fInfo->Name, isReadOnly);

    // Set the file to read-only.
    Console::WriteLine("Setting the read-only value for '{0}' to true.", fInfo->Name);
    fInfo->IsReadOnly = true;

    // Get the read-only value for a file.
    isReadOnly = fInfo->IsReadOnly;

    // Display that the file is now read-only.
    Console::WriteLine("The file read-only value for '{0}' is {1}.", fInfo->Name, isReadOnly);

    // Make the file mutable again so it can be deleted.
    fInfo->IsReadOnly = false;

    // Delete the temporary file.
    fInfo->Delete();

    return 0;
};

// This code produces output similar to the following,
// though results may vary based on the computer, file structure, etc.:
//
// Created a temp file at 'C:\Users\UserName\AppData\Local\Temp\tmpB438.tmp'.
// The file read-only value for 'tmpB438.tmp' is False.
// Setting the read-only value for 'tmpB438.tmp' to true.
// The file read-only value for 'tmpB438.tmp' is True.
//

using System;
using System.IO;

public class FileExample
{
    public static void Main()
    {
        // Create a temporary file.
        string filePath = Path.GetTempFileName();
        Console.WriteLine($"Created a temp file at '{filePath}'.");

        // Create a new FileInfo object.
        FileInfo fInfo = new FileInfo(filePath);

        // Get the read-only value for a file.
        bool isReadOnly = fInfo.IsReadOnly;

        // Display whether the file is read-only.
        Console.WriteLine($"The file read-only value for '{fInfo.Name}' is {isReadOnly}.");

        // Set the file to read-only.        
        Console.WriteLine($"Setting the read-only value for '{fInfo.Name}' to true.");
        fInfo.IsReadOnly = true;

        // Get the read-only value for a file.
        isReadOnly = fInfo.IsReadOnly;

        // Display that the file is now read-only.
        Console.WriteLine($"The file read-only value for '{fInfo.Name}' is {isReadOnly}.");

        // Make the file mutable again so it can be deleted.
        fInfo.IsReadOnly = false;

        // Delete the temporary file.
        fInfo.Delete();
    }
}

// This code produces output similar to the following,
// though results may vary based on the computer, file structure, etc.:
//
// Created a temp file at 'C:\Users\UserName\AppData\Local\Temp\tmpB438.tmp'.
// The file read-only value for 'tmpB438.tmp' is False.
// Setting the read-only value for 'tmpB438.tmp' to true.
// The file read-only value for 'tmpB438.tmp' is True.
//

Imports System.IO

Module FileExample

    Sub Main()

        ' Create a temporary file.
        Dim filePath As String = Path.GetTempFileName()
        Console.WriteLine($"Created a temp file at '{filePath}'.")

        ' Create a new FileInfo object.
        Dim fInfo As New FileInfo(filePath)

        ' Get the read-only value for a file.
        Dim isReadOnly As Boolean = fInfo.IsReadOnly

        ' Display whether the file is read-only.
        Console.WriteLine($"The file read-only value for '{fInfo.Name}' is {isReadOnly}.")

        ' Set the file to read-only.
        Console.WriteLine($"Setting the read-only value for '{fInfo.Name}' to true.")
        fInfo.IsReadOnly = True

        ' Get the read-only value for a file.
        isReadOnly = fInfo.IsReadOnly

        ' Display that the file is now read-only.
        Console.WriteLine($"The file read-only value for '{fInfo.Name}' is {isReadOnly}.")

        ' Make the file mutable again so it can be deleted.
        fInfo.IsReadOnly = False

        ' Delete the temporary file.
        fInfo.Delete()
    End Sub

End Module

' This code produces output similar to the following,
' though results may vary based on the computer, file structure, etc.:
'
' Created a temp file at 'C:\Users\UserName\AppData\Local\Temp\tmpB438.tmp'.
' The file read-only value for 'tmpB438.tmp' is False.
' Setting the read-only value for 'tmpB438.tmp' to true.
' The file read-only value for 'tmpB438.tmp' is True.
'

Remarks

Use the IsReadOnly property to quickly determine or change whether the current file is read only.

If the current file does not exist, getting this property will always return true, but attempts to set will throw a FileNotFoundException.

When first called, FileInfo calls Refresh and caches information about the file. On subsequent calls, you must call Refresh to get the latest copy of the information.