Exception.GetBaseException-Methode
Gibt beim Überschreiben in einer abgeleiteten Klasse eine Exception zurück, die die ursprüngliche Ursache für eine oder mehrere nachfolgende Ausnahmen ist.
Namespace: System
Assembly: mscorlib (in mscorlib.dll)
Syntax
'Declaration
Public Overridable Function GetBaseException As Exception
'Usage
Dim instance As Exception
Dim returnValue As Exception
returnValue = instance.GetBaseException
public virtual Exception GetBaseException ()
public:
virtual Exception^ GetBaseException ()
public Exception GetBaseException ()
public function GetBaseException () : Exception
Rückgabewert
Die erste Ausnahme, die in einer Kette von Ausnahmen ausgelöst wird. Wenn die InnerException-Eigenschaft der aktuellen Ausnahme ein NULL-Verweis (Nothing in Visual Basic) ist, gibt diese Eigenschaft die aktuelle Ausnahme zurück.
Hinweise
Als Kette von Ausnahmen wird eine Reihe von Ausnahmen bezeichnet, bei der jede Ausnahme als direkte Folge der Ausnahme, auf die ihre InnerException-Eigenschaft verweist, ausgelöst wurde. In einer Kette gibt es nur eine einzige Ausnahme, die die ursprüngliche Ursache aller anderen Ausnahmen ist. Diese Ausnahme wird als Basisausnahme bezeichnet. Ihre InnerException-Eigenschaft enthält immer einen NULL-Verweis.
Die GetBaseException-Methode muss für alle Ausnahmen in der Kette von Ausnahmen dasselbe Objekt (die Basisausnahme) zurückgeben.
Verwenden Sie die GetBaseException-Methode, wenn Sie die ursprüngliche Ursache suchen, jedoch keine Informationen über Ausnahmen benötigen, die zwischen der ersten und der aktuellen Ausnahme ausgelöst wurden.
Hinweise für Erben Die GetBaseException-Eigenschaft wird in Klassen überschrieben, die den Inhalt oder das Format von Ausnahmen steuern müssen.
Beispiel
Im folgenden Codebeispiel werden zwei abgeleitete Exception-Klassen definiert. Eine Ausnahme wird erzwungen, die dann noch einmal mit beiden abgeleiteten Klassen ausgelöst wird. Der Code veranschaulicht die Verwendung der GetBaseException-Methode zum Abrufen der ursprünglichen Ausnahme.
' Example for the Exception.GetBaseException method.
Imports System
Imports Microsoft.VisualBasic
Namespace NDP_UE_VB
' Define two derived exceptions to demonstrate nested exceptions.
Class SecondLevelException
Inherits Exception
Public Sub New( message As String, inner As Exception )
MyBase.New( message, inner )
End Sub ' New
End Class ' SecondLevelException
Class ThirdLevelException
Inherits Exception
Public Sub New( message As String, inner As Exception )
MyBase.New( message, inner )
End Sub ' New
End Class ' ThirdLevelException
Class NestedExceptions
Public Shared Sub Main( )
Console.WriteLine( _
"This example of Exception.GetBaseException " & _
"generates the following output." )
Console.WriteLine( vbCrLf & _
"The program forces a division by 0, then throws " & _
"the exception " & vbCrLf & "twice more, using " & _
"a different derived exception each time:" & vbCrLf )
Try
' This sub calls another that forces a division by 0.
Rethrow()
Catch ex As Exception
Dim current As Exception
Console.WriteLine( _
"Unwind the nested exceptions using the " & _
"InnerException property:" & vbCrLf )
' This code unwinds the nested exceptions using the
' InnerException property.
current = ex
While Not ( current Is Nothing )
Console.WriteLine( current.ToString( ) )
Console.WriteLine( )
current = current.InnerException
End While
' Display the innermost exception.
Console.WriteLine( _
"Display the base exception using the " & _
"GetBaseException method:" & vbCrLf )
Console.WriteLine( _
ex.GetBaseException( ).ToString( ) )
End Try
End Sub ' Main
' This sub catches the exception from the called sub
' DivideBy0( ) and throws another in response.
Shared Sub Rethrow( )
Try
DivideBy0( )
Catch ex As Exception
Throw New ThirdLevelException( _
"Caught the second exception and " & _
"threw a third in response.", ex )
End Try
End Sub ' Rethrow
' This sub forces a division by 0 and throws a second
' exception.
Shared Sub DivideBy0( )
Try
Dim zero As Integer = 0
Dim ecks As Integer = 1 \ zero
Catch ex As Exception
Throw New SecondLevelException( _
"Forced a division by 0 and threw " & _
"a second exception.", ex )
End Try
End Sub ' DivideBy0
End Class ' NestedExceptions
End Namespace ' NDP_UE_VB
' This example of Exception.GetBaseException generates the following output.
'
' The program forces a division by 0, then throws the exception
' twice more, using a different derived exception each time:
'
' Unwind the nested exceptions using the InnerException property:
'
' NDP_UE_VB.ThirdLevelException: Caught the second exception and threw a third
' in response. ---> NDP_UE_VB.SecondLevelException: Forced a division by 0 and
' threw a second exception. ---> System.DivideByZeroException: Attempted to div
' ide by zero.
' at NDP_UE_VB.NestedExceptions.DivideBy0()
' --- End of inner exception stack trace ---
' at NDP_UE_VB.NestedExceptions.DivideBy0()
' at NDP_UE_VB.NestedExceptions.Rethrow()
' --- End of inner exception stack trace ---
' at NDP_UE_VB.NestedExceptions.Rethrow()
' at NDP_UE_VB.NestedExceptions.Main()
'
' NDP_UE_VB.SecondLevelException: Forced a division by 0 and threw a second exc
' eption. ---> System.DivideByZeroException: Attempted to divide by zero.
' at NDP_UE_VB.NestedExceptions.DivideBy0()
' --- End of inner exception stack trace ---
' at NDP_UE_VB.NestedExceptions.DivideBy0()
' at NDP_UE_VB.NestedExceptions.Rethrow()
'
' System.DivideByZeroException: Attempted to divide by zero.
' at NDP_UE_VB.NestedExceptions.DivideBy0()
'
' Display the base exception using the GetBaseException method:
'
' System.DivideByZeroException: Attempted to divide by zero.
' at NDP_UE_VB.NestedExceptions.DivideBy0()
// Example for the Exception.GetBaseException method.
using System;
namespace NDP_UE_CS
{
// Define two derived exceptions to demonstrate nested exceptions.
class SecondLevelException : Exception
{
public SecondLevelException( string message, Exception inner )
: base( message, inner )
{ }
}
class ThirdLevelException : Exception
{
public ThirdLevelException( string message, Exception inner )
: base( message, inner )
{ }
}
class NestedExceptions
{
public static void Main()
{
Console.WriteLine(
"This example of Exception.GetBaseException " +
"generates the following output." );
Console.WriteLine(
"\nThe program forces a division by 0, then " +
"throws the exception \ntwice more, " +
"using a different derived exception each time.\n" );
try
{
// This function calls another that forces a
// division by 0.
Rethrow( );
}
catch( Exception ex )
{
Exception current;
Console.WriteLine(
"Unwind the nested exceptions " +
"using the InnerException property:\n" );
// This code unwinds the nested exceptions using the
// InnerException property.
current = ex;
while( current != null )
{
Console.WriteLine( current.ToString( ) );
Console.WriteLine( );
current = current.InnerException;
}
// Display the innermost exception.
Console.WriteLine(
"Display the base exception " +
"using the GetBaseException method:\n" );
Console.WriteLine(
ex.GetBaseException( ).ToString( ) );
}
}
// This function catches the exception from the called
// function DivideBy0( ) and throws another in response.
static void Rethrow()
{
try
{
DivideBy0( );
}
catch( Exception ex )
{
throw new ThirdLevelException(
"Caught the second exception and " +
"threw a third in response.", ex );
}
}
// This function forces a division by 0 and throws a second
// exception.
static void DivideBy0( )
{
try
{
int zero = 0;
int ecks = 1 / zero;
}
catch( Exception ex )
{
throw new SecondLevelException(
"Forced a division by 0 and threw " +
"a second exception.", ex );
}
}
}
}
/*
This example of Exception.GetBaseException generates the following output.
The program forces a division by 0, then throws the exception
twice more, using a different derived exception each time.
Unwind the nested exceptions using the InnerException property:
NDP_UE_CS.ThirdLevelException: Caught the second exception and threw a third in
response. ---> NDP_UE_CS.SecondLevelException: Forced a division by 0 and thre
w a second exception. ---> System.DivideByZeroException: Attempted to divide by
zero.
at NDP_UE_CS.NestedExceptions.DivideBy0()
--- End of inner exception stack trace ---
at NDP_UE_CS.NestedExceptions.DivideBy0()
at NDP_UE_CS.NestedExceptions.Rethrow()
--- End of inner exception stack trace ---
at NDP_UE_CS.NestedExceptions.Rethrow()
at NDP_UE_CS.NestedExceptions.Main()
NDP_UE_CS.SecondLevelException: Forced a division by 0 and threw a second excep
tion. ---> System.DivideByZeroException: Attempted to divide by zero.
at NDP_UE_CS.NestedExceptions.DivideBy0()
--- End of inner exception stack trace ---
at NDP_UE_CS.NestedExceptions.DivideBy0()
at NDP_UE_CS.NestedExceptions.Rethrow()
System.DivideByZeroException: Attempted to divide by zero.
at NDP_UE_CS.NestedExceptions.DivideBy0()
Display the base exception using the GetBaseException method:
System.DivideByZeroException: Attempted to divide by zero.
at NDP_UE_CS.NestedExceptions.DivideBy0()
*/
// Example for the Exception::GetBaseException method.
using namespace System;
namespace NDP_UE_CPP
{
// Define two derived exceptions to demonstrate nested exceptions.
ref class SecondLevelException: public Exception
{
public:
SecondLevelException( String^ message, Exception^ inner )
: Exception( message, inner )
{}
};
ref class ThirdLevelException: public Exception
{
public:
ThirdLevelException( String^ message, Exception^ inner )
: Exception( message, inner )
{}
};
// DivideBy0 forces a division by 0 and throws a second exception.
void DivideBy0()
{
try
{
int zero = 0;
int ecks = 1 / zero;
}
catch ( Exception^ ex )
{
throw gcnew SecondLevelException( "Forced a division by 0 and threw "
"a second exception.",ex );
}
}
// This function catches the exception from the called function
// DivideBy0( ) and throws another in response.
void Rethrow()
{
try
{
DivideBy0();
}
catch ( Exception^ ex )
{
throw gcnew ThirdLevelException( "Caught the second exception and "
"threw a third in response.",ex );
}
}
}
int main()
{
Console::WriteLine( "This example of Exception.GetBaseException "
"generates the following output." );
Console::WriteLine( "\nThe program forces a division by 0, "
"then throws the exception \ntwice more, "
"using a different derived exception each time.\n" );
try
{
// This function calls another that forces a division by 0.
NDP_UE_CPP::Rethrow();
}
catch ( Exception^ e )
{
Exception^ current;
Console::WriteLine( "Unwind the nested exceptions using "
"the InnerException property:\n" );
// This code unwinds the nested exceptions using the
// InnerException property.
current = e;
while ( current != (Object^)0 )
{
Console::WriteLine( current->ToString() );
Console::WriteLine();
current = current->InnerException;
}
// Display the innermost exception.
Console::WriteLine( "Display the base exception using the \n"
"GetBaseException method:\n" );
Console::WriteLine( e->GetBaseException()->ToString() );
}
}
/*
This example of Exception.GetBaseException generates the following output.
The program forces a division by 0, then throws the exception
twice more, using a different derived exception each time.
Unwind the nested exceptions using the InnerException property:
NDP_UE_CPP.ThirdLevelException: Caught the second exception and threw a third i
n response. ---> NDP_UE_CPP.SecondLevelException: Forced a division by 0 and th
rew a second exception. ---> System.DivideByZeroException: Attempted to divide
by zero.
at NDP_UE_CPP.DivideBy0()
--- End of inner exception stack trace ---
at NDP_UE_CPP.DivideBy0()
at NDP_UE_CPP.Rethrow()
--- End of inner exception stack trace ---
at NDP_UE_CPP.Rethrow()
at main()
NDP_UE_CPP.SecondLevelException: Forced a division by 0 and threw a second exce
ption. ---> System.DivideByZeroException: Attempted to divide by zero.
at NDP_UE_CPP.DivideBy0()
--- End of inner exception stack trace ---
at NDP_UE_CPP.DivideBy0()
at NDP_UE_CPP.Rethrow()
System.DivideByZeroException: Attempted to divide by zero.
at NDP_UE_CPP.DivideBy0()
Display the base exception using the
GetBaseException method:
System.DivideByZeroException: Attempted to divide by zero.
at NDP_UE_CPP.DivideBy0()
*/
// Example for the Exception.GetBaseException method.
package NDP_UE_JSL;
import System.* ;
// Define two derived exceptions to demonstrate nested exceptions.
class SecondLevelException extends System.Exception
{
public SecondLevelException(String message, System.Exception inner)
{
super(message, inner);
} //SecondLevelException
} //SecondLevelException
class ThirdLevelException extends System.Exception
{
public ThirdLevelException(String message, System.Exception inner)
{
super(message, inner);
} //ThirdLevelException
} //ThirdLevelException
class NestedExceptions
{
public static void main(String[] args)
{
Console.WriteLine(("This example of Exception.GetBaseException "
+ "generates the following output."));
Console.WriteLine(("\nThe program forces a division by 0, then "
+ "throws the exception \ntwice more, "
+ "using a different derived exception each time.\n"));
try {
// This function calls another that forces a
// division by 0.
Rethrow();
}
catch (System.Exception ex) {
System.Exception current;
Console.WriteLine(("Unwind the nested exceptions "
+ "using the InnerException property:\n"));
// This code unwinds the nested exceptions using the
// InnerException property.
current = ex;
while ((current != null)) {
Console.WriteLine(current.ToString());
Console.WriteLine();
current = current.get_InnerException();
}
// Display the innermost exception.
Console.WriteLine(("Display the base exception "
+ "using the GetBaseException method:\n"));
Console.WriteLine(ex.GetBaseException().ToString());
}
} //main
// This function catches the exception from the called
// function DivideBy0( ) and throws another in response.
static void Rethrow() throws ThirdLevelException ,SecondLevelException
{
try {
DivideBy0();
}
catch (System.Exception ex) {
throw new ThirdLevelException("Caught the second exception and "
+ "threw a third in response.", ex);
}
} //Rethrow
// This function forces a division by 0 and throws a second
// exception.
static void DivideBy0() throws SecondLevelException
{
try {
int zero = 0;
int ecks = 1 / zero;
}
catch (System.Exception ex) {
throw new SecondLevelException(
"Forced a division by 0 and threw "
+ "a second exception.", ex);
}
} //DivideBy0
} //NestedExceptions
/*
This example of Exception.GetBaseException generates the following output.
The program forces a division by 0, then throws the exception
twice more, using a different derived exception each time.
Unwind the nested exceptions using the InnerException property:
NDP_UE_JSL.ThirdLevelException: Caught the second exception and threw a third in
response. ---> NDP_UE_JSL.SecondLevelException: Forced a division by 0 and thre
w a second exception. ---> System.DivideByZeroException: Attempted to divide by
zero.
at NDP_UE_JSL.NestedExceptions.DivideBy0() in C:\Documents and Settings\
My Documents\Visual Studio Projects\ConsoleApp - JS\ConsoleApp - JS\
Class1.jsl:line 79
--- End of inner exception stack trace ---
at NDP_UE_JSL.NestedExceptions.DivideBy0() in C:\Documents and Settings\
My Documents\Visual Studio Projects\ConsoleApp - JS\ConsoleApp - JS\
Class1.jsl:line 82
at NDP_UE_JSL.NestedExceptions.Rethrow() in C:\Documents and Settings\
My Documents\Visual Studio Projects\ConsoleApp - JS\ConsoleApp - JS\Cl
ass1.jsl:line 65
--- End of inner exception stack trace ---
at NDP_UE_JSL.NestedExceptions.Rethrow() in C:\Documents and Settings\
My Documents\Visual Studio Projects\ConsoleApp - JS\ConsoleApp - JS\Cl
ass1.jsl:line 68
at NDP_UE_JSL.NestedExceptions.main(String[] args) in C:\Documents and
Settings\My Documents\Visual Studio Projects\ConsoleApp - JS\ConsoleA
pp - JS\Class1.jsl:line 36
NDP_UE_JSL.SecondLevelException: Forced a division by 0 and threw a second
exception. ---> System.DivideByZeroException: Attempted to divide by zero.
at NDP_UE_JSL.NestedExceptions.DivideBy0() in C:\Documents and Settings\
My Documents\Visual Studio Projects\ConsoleApp - JS\ConsoleApp - JS\
Class1.jsl:line 79
--- End of inner exception stack trace ---
at NDP_UE_JSL.NestedExceptions.DivideBy0() in C:\Documents and Settings\
My Documents\Visual Studio Projects\ConsoleApp - JS\ConsoleApp - JS\
Class1.jsl:line 82
at NDP_UE_JSL.NestedExceptions.Rethrow() in C:\Documents and Settings\
My Documents\Visual Studio Projects\ConsoleApp - JS\ConsoleApp - JS\Cl
ass1.jsl:line 65
System.DivideByZeroException: Attempted to divide by zero.
at NDP_UE_JSL.NestedExceptions.DivideBy0() in C:\Documents and Settings\
My Documents\Visual Studio Projects\ConsoleApp - JS\ConsoleApp - JS\
Class1.jsl:line 79
Display the base exception using the GetBaseException method:
System.DivideByZeroException: Attempted to divide by zero.
at NDP_UE_JSL.NestedExceptions.DivideBy0() in C:\Documents and Settings\
My Documents\Visual Studio Projects\ConsoleApp - JS\ConsoleApp - JS\
Class1.jsl:line 79
*/
Plattformen
Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile für Pocket PC, Windows Mobile für Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
.NET Framework unterstützt nicht alle Versionen sämtlicher Plattformen. Eine Liste der unterstützten Versionen finden Sie unter Systemanforderungen.
Versionsinformationen
.NET Framework
Unterstützt in: 2.0, 1.1, 1.0
.NET Compact Framework
Unterstützt in: 2.0, 1.0