UnauthorizedAccessException Class
The exception that is thrown when the operating system denies access because of an I/O error or a specific type of security error.
Assembly: mscorlib (in mscorlib.dll)
System.Exception
System.SystemException
System.UnauthorizedAccessException
System.Security.AccessControl.PrivilegeNotHeldException
| Name | Description | |
|---|---|---|
![]() | UnauthorizedAccessException() | Initializes a new instance of the UnauthorizedAccessException class. |
![]() | UnauthorizedAccessException(SerializationInfo, StreamingContext) | Initializes a new instance of the UnauthorizedAccessException class with serialized data. |
![]() | UnauthorizedAccessException(String) | Initializes a new instance of the UnauthorizedAccessException class with a specified error message. |
![]() | UnauthorizedAccessException(String, Exception) | Initializes a new instance of the UnauthorizedAccessException class with a specified error message and a reference to the inner exception that is the cause of this exception. |
| Name | Description | |
|---|---|---|
![]() | Data | Gets a collection of key/value pairs that provide additional user-defined information about the exception.(Inherited from Exception.) |
![]() | HelpLink | Gets or sets a link to the help file associated with this exception.(Inherited from Exception.) |
![]() | HResult | Gets or sets HRESULT, a coded numerical value that is assigned to a specific exception.(Inherited from Exception.) |
![]() | InnerException | |
![]() | Message | Gets a message that describes the current exception.(Inherited from Exception.) |
![]() | Source | Gets or sets the name of the application or the object that causes the error.(Inherited from Exception.) |
![]() | StackTrace | Gets a string representation of the immediate frames on the call stack.(Inherited from Exception.) |
![]() | TargetSite | Gets the method that throws the current exception.(Inherited from Exception.) |
| Name | Description | |
|---|---|---|
![]() | Equals(Object) | Determines whether the specified object is equal to the current object.(Inherited from Object.) |
![]() | Finalize() | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.(Inherited from Object.) |
![]() | GetBaseException() | |
![]() | GetHashCode() | Serves as the default hash function. (Inherited from Object.) |
![]() | GetObjectData(SerializationInfo, StreamingContext) | When overridden in a derived class, sets the SerializationInfo with information about the exception.(Inherited from Exception.) |
![]() | GetType() | Gets the runtime type of the current instance.(Inherited from Exception.) |
![]() | MemberwiseClone() | |
![]() | ToString() | Creates and returns a string representation of the current exception.(Inherited from Exception.) |
| Name | Description | |
|---|---|---|
![]() | SerializeObjectState | Occurs when an exception is serialized to create an exception state object that contains serialized data about the exception.(Inherited from Exception.) |
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 HRESULTCOR_E_UNAUTHORIZEDACCESS, which has the value 0x80070005.
The following example illustrates theUnauthorizedAccessException 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.
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
Any public static ( Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.



