This documentation is archived and is not being maintained.

Exception.InnerException Property

Gets the Exception instance that caused the current exception.

Namespace: System
Assembly: mscorlib (in mscorlib.dll)

Public ReadOnly Property InnerException As Exception
Dim instance As Exception
Dim value As Exception

value = instance.InnerException

/** @property */
public final Exception get_InnerException ()

public final function get InnerException () : Exception

Property Value

An instance of Exception that describes the error that caused the current exception. The InnerException property returns the same value as was passed into the constructor, or a null reference (Nothing in Visual Basic) if the inner exception value was not supplied to the constructor. This property is read-only.

When an exception X is thrown as a direct result of a previous exception Y, the InnerException property of X should contain a reference to Y.

Use the InnerException property to obtain the set of exceptions that led to the current exception.

You can create a new exception that catches an earlier exception. The code that handles the second exception can make use of the additional information from the earlier exception to handle the error more appropriately.

Suppose that there is a function that reads a file and formats the data from that file. In this example, as the code tries to read the file, an IOException is thrown. The function catches the IOException and throws a FileNotFoundException. The IOException could be saved in the InnerException property of the FileNotFoundException, enabling the code that catches the FileNotFoundException to examine what causes the initial error.

The InnerException property, which holds a reference to the inner exception, is set upon initialization of the exception object.

The following example demonstrates throwing and catching an exception that references an inner exception.

Imports System

Public Class MyAppException
   Inherits ApplicationException
   Public Sub New(message As [String])
   End Sub 'New
   Public Sub New(message As [String], inner As Exception)
      MyBase.New(message, inner)
   End Sub 'New
End Class 'MyAppException

Public Class ExceptExample
   Public Sub ThrowInner()
      Throw New MyAppException("ExceptExample inner exception")
   End Sub 'ThrowInner
   Public Sub CatchInner()
      Catch e As Exception
         Throw New MyAppException("Error caused by trying ThrowInner.", e)
      End Try
   End Sub 'CatchInner
End Class 'ExceptExample

Public Class Test
   Public Shared Sub Main()
      Dim testInstance As New ExceptExample()
      Catch e As Exception
         Console.WriteLine("In Main catch block. Caught: {0}", e.Message)
         Console.WriteLine("Inner Exception is {0}", e.InnerException)
      End Try
   End Sub 'Main
End Class 'Test

import System.*;
public class MyAppException extends ApplicationException
    public MyAppException(String message)
    } //MyAppException

    public MyAppException(String message, System.Exception inner)
      super(message, inner);
    } //MyAppException
} //MyAppException

public class ExceptExample
    public void ThrowInner()throws MyAppException
        throw new MyAppException("ExceptExample inner exception");
    } //ThrowInner

    public void CatchInner()throws MyAppException
        try {
        catch (System.Exception e) {
            throw new MyAppException("Error caused by trying ThrowInner.", e);
    } //CatchInner
} //ExceptExample

public class Test
    public static void main(String[] args)
        ExceptExample testInstance = new ExceptExample();
        try {
        catch (System.Exception e) {
            Console.WriteLine("In main catch block. Caught: {0}", 
            Console.WriteLine("Inner Exception is {0}", 
    } //main
} //Test

This code has the following output:

In Main
  catch block. Caught: Error caused by trying ThrowInner. Inner Exception is
  MyAppException: ExceptExample inner exception at ExceptExample.ThrowInner() at

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0