Gets the Exception instance that caused the current exception.
Assembly: mscorlib (in mscorlib.dll)
Property ValueType: System.Exception
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 property of the FileNotFoundException, enabling the code that catches the FileNotFoundException to examine what causes the initial error.
The 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.
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 ExceptExample.CatchInner()
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.