UnauthorizedAccessException Class

Definition

public ref class UnauthorizedAccessException : Exception

public ref class UnauthorizedAccessException : SystemException

public class UnauthorizedAccessException : Exception

public class UnauthorizedAccessException : SystemException

[System.Serializable]
public class UnauthorizedAccessException : SystemException

[System.Serializable]
[System.Runtime.InteropServices.ComVisible(true)]
public class UnauthorizedAccessException : SystemException

type UnauthorizedAccessException = class
    inherit Exception

type UnauthorizedAccessException = class
    inherit SystemException

[<System.Serializable>]
type UnauthorizedAccessException = class
    inherit SystemException

[<System.Serializable>]
[<System.Runtime.InteropServices.ComVisible(true)>]
type UnauthorizedAccessException = class
    inherit SystemException

Public Class UnauthorizedAccessException
Inherits Exception

Public Class UnauthorizedAccessException
Inherits SystemException

Inheritance

Object

Exception

UnauthorizedAccessException

Inheritance

Object

Exception

SystemException

UnauthorizedAccessException

Derived

System.Security.AccessControl.PrivilegeNotHeldException

Attributes

SerializableAttribute ComVisibleAttribute

Examples

The following example illustrates the UnauthorizedAccessException exception that is thrown when attempting to write to a read-only file.

using System;
using System.IO;

public class Example
{
   public static void Main()
   {
      string filePath = @".\ROFile.txt";
      if (! File.Exists(filePath))
         File.Create(filePath);
      // Keep existing attributes, and set ReadOnly attribute.
      File.SetAttributes(filePath, 
                        (new FileInfo(filePath)).Attributes | FileAttributes.ReadOnly);

      StreamWriter sw = null;
      try {
         sw = new StreamWriter(filePath);
         sw.Write("Test");
      }
      catch (UnauthorizedAccessException) {
         FileAttributes attr = (new FileInfo(filePath)).Attributes;
         Console.Write("UnAuthorizedAccessException: Unable to access file. ");
         if ((attr & FileAttributes.ReadOnly) > 0)
            Console.Write("The file is read-only."); 
       }
       finally {
         if (sw != null) sw.Close();
      }   
   }
}
// The example displays the following output:
//    UnAuthorizedAccessException: Unable to access file. The file is read-only.

open System
open System.IO


let filePath = @".\ROFile.txt"
if File.Exists filePath |> not then
    File.Create filePath |> ignore
// Keep existing attributes, and set ReadOnly attribute.
File.SetAttributes(filePath, (FileInfo filePath).Attributes ||| FileAttributes.ReadOnly)

do
    use sw = new StreamWriter(filePath)
    try
        sw.Write "Test"
    with :? UnauthorizedAccessException ->
        let attr = (FileInfo filePath).Attributes
        printf "UnAuthorizedAccessException: Unable to access file. "
        if int (attr &&& FileAttributes.ReadOnly) > 0 then
            printf "The file is read-only."
// The example displays the following output:
//    UnAuthorizedAccessException: Unable to access file. The file is read-only.

Imports System.IO

Module Example
   Public Sub Main()
      Dim filePath As String = ".\ROFile.txt"
      If Not File.Exists(filePath) Then File.Create(filePath)
      ' Keep existing attributes, and set ReadOnly attribute.
      File.SetAttributes(filePath, 
                        (New FileInfo(filePath)).Attributes Or FileAttributes.ReadOnly)

      Dim sw As StreamWriter = Nothing
      Try
         sw = New StreamWriter(filePath)
         sw.Write("Test")
      Catch e As UnauthorizedAccessException
         Dim attr As FileAttributes = (New FileInfo(filePath)).Attributes
         Console.Write("UnAuthorizedAccessException: Unable to access file. ")
         If (attr And FileAttributes.ReadOnly) > 0 Then
            Console.Write("The file is read-only.") 
         End If
       Finally
         If sw IsNot Nothing Then sw.Close()
      End Try   
   End Sub
End Module
' The example displays the following output:
'   UnAuthorizedAccessException: Unable to access file. The file is read-only.

Remarks

An UnauthorizedAccessException exception is typically thrown by a method that wraps a Windows API call. To find the reasons for the exception, examine the text of the exception object's Message property.

UnauthorizedAccessException uses the HRESULT COR_E_UNAUTHORIZEDACCESS, which has the value 0x80070005.

Constructors

Properties

Methods

Events

Applies to

See also

• Exception
• Handling and Throwing Exceptions