DecoderFallbackException Klasse
Definition
Wichtig
Einige Informationen beziehen sich auf Vorabversionen, die vor dem Release ggf. grundlegend überarbeitet werden. Microsoft übernimmt hinsichtlich der hier bereitgestellten Informationen keine Gewährleistungen, seien sie ausdrücklich oder konkludent.
Die Ausnahme, die ausgelöst wird, wenn ein Decoderfallback fehlschlägt. Diese Klasse kann nicht vererbt werden.
public ref class DecoderFallbackException sealed : ArgumentExceptionpublic sealed class DecoderFallbackException : ArgumentException[System.Serializable]
public sealed class DecoderFallbackException : ArgumentExceptiontype DecoderFallbackException = class
inherit ArgumentException[<System.Serializable>]
type DecoderFallbackException = class
inherit ArgumentExceptionPublic NotInheritable Class DecoderFallbackException
Inherits ArgumentException- Vererbung
- Vererbung
- Attribute
Beispiele
Im folgenden Codebeispiel werden die DecoderExceptionFallback Klassen und DecoderFallbackException veranschaulicht.
// This example demonstrates the DecoderExceptionFallback class.
using namespace System;
using namespace System::Text;
int main()
{
// Create an encoding, which is equivalent to calling the
// ASCIIEncoding class constructor.
// The DecoderExceptionFallback parameter specifies that an exception
// is thrown if a character cannot be encoded.
// An encoder exception fallback is also specified, but in this code
// example the encoding operation cannot fail.
Encoding^ asciiEncoding = Encoding::GetEncoding("us-ascii",
gcnew EncoderExceptionFallback(), gcnew DecoderExceptionFallback());
String^ inputString = "XYZ";
String^ decodedString;
String^ twoNewLines = Environment::NewLine + Environment::NewLine ;
array<Byte>^ encodedBytes =
gcnew array<Byte>(asciiEncoding->GetByteCount(inputString));
int numberOfEncodedBytes = 0;
// ---------------------------------------------------------------------
Console::Clear();
// Display the name of the encoding.
Console::WriteLine("The name of the encoding is \"{0}\".{1}",
asciiEncoding->WebName, Environment::NewLine);
// Display the input string in text.
Console::WriteLine("Input string ({0} characters): \"{1}\"",
inputString->Length, inputString);
// Display the input string in hexadecimal.
Console::Write("Input string in hexadecimal: ");
for each (char c in inputString)
{
Console::Write("0x{0:X2} ", c);
}
Console::Write(twoNewLines);
// ---------------------------------------------------------------------
// Encode the input string.
Console::WriteLine("Encode the input string...");
numberOfEncodedBytes = asciiEncoding->GetBytes(inputString, 0,
inputString->Length, encodedBytes, 0);
// Display the encoded bytes.
Console::WriteLine("Encoded bytes in hexadecimal ({0} bytes):{1}",
numberOfEncodedBytes, Environment::NewLine);
for each (Byte b in encodedBytes)
{
Console::Write("0x{0:X2} ", b);
}
Console::Write(twoNewLines);
// ---------------------------------------------------------------------
// Replace the encoded byte sequences for the characters 'X' and 'Z'
// with the value 0xFF, which is outside the valid range of 0x00 to 0x7F
// for ASCIIEncoding. The resulting byte sequence is actually the
// beginning of this code example because it is the input to the decoder
// operation, and is equivalent to a corrupted or improperly encoded
// byte sequence.
encodedBytes[0] = 0xFF;
encodedBytes[2] = 0xFF;
Console::WriteLine("Display the corrupted byte sequence...");
Console::WriteLine("Encoded bytes in hexadecimal ({0} bytes):{1}",
numberOfEncodedBytes, Environment::NewLine);
for each (Byte b in encodedBytes)
{
Console::Write("0x{0:X2} ", b);
}
Console::Write(twoNewLines);
// ---------------------------------------------------------------------
// Attempt to decode the encoded bytes. However, an exception is thrown
// before the byte sequence can be decoded.
Console::WriteLine("Compare the decoded bytes to the input string...");
try
{
decodedString = asciiEncoding->GetString(encodedBytes);
// This statement is never executed.
Console::WriteLine("This statement is never executed.");
}
catch (DecoderFallbackException^ ex)
{
Console::WriteLine(ex);
Console::WriteLine(
"{0}*** THE CODE EXAMPLE TERMINATES HERE AS INTENDED. ***",
Environment::NewLine);
}
}
/*
This code example produces the following results:
The name of the encoding is "us-ascii".
Input string (3 characters): "XYZ"
Input string in hexadecimal: 0x58 0x59 0x5A
Encode the input string...
Encoded bytes in hexadecimal (3 bytes):
0x58 0x59 0x5A
Display the corrupted byte sequence...
Encoded bytes in hexadecimal (3 bytes):
0xFF 0x59 0xFF
Compare the decoded bytes to the input string...
System.Text.DecoderFallbackException: Unable to translate bytes [FF] at index 0 from speci
fied code page to Unicode.
at System.Text.DecoderExceptionFallbackBuffer.Throw(Byte[] bytesUnknown, Int32 index)
at System.Text.DecoderExceptionFallbackBuffer.Fallback(Byte[] bytesUnknown, Int32 index
)
at System.Text.DecoderFallbackBuffer.InternalFallback(Byte[] bytes, Byte* pBytes)
at System.Text.ASCIIEncoding.GetCharCount(Byte* bytes, Int32 count, DecoderNLS decoder)
at System.String.CreateStringFromEncoding(Byte* bytes, Int32 byteLength, Encoding encod
ing)
at System.Text.ASCIIEncoding.GetString(Byte[] bytes, Int32 byteIndex, Int32 byteCount)
at System.Text.Encoding.GetString(Byte[] bytes)
at Sample.Main()
*** THE CODE EXAMPLE TERMINATES HERE AS INTENDED. ***
*/
// This example demonstrates the DecoderExceptionFallback class.
using System;
using System.Text;
class Sample
{
public static void Main()
{
// Create an encoding, which is equivalent to calling the
// ASCIIEncoding class constructor.
// The DecoderExceptionFallback parameter specifies that an exception
// is thrown if a character cannot be encoded.
// An encoder exception fallback is also specified, but in this code
// example the encoding operation cannot fail.
Encoding ae = Encoding.GetEncoding(
"us-ascii",
new EncoderExceptionFallback(),
new DecoderExceptionFallback());
string inputString = "XYZ";
string decodedString;
string twoNewLines = "\n\n";
byte[] encodedBytes = new byte[ae.GetByteCount(inputString)];
int numberOfEncodedBytes = 0;
// --------------------------------------------------------------------------
Console.Clear();
// Display the name of the encoding.
Console.WriteLine("The name of the encoding is \"{0}\".\n", ae.WebName);
// Display the input string in text.
Console.WriteLine("Input string ({0} characters): \"{1}\"",
inputString.Length, inputString);
// Display the input string in hexadecimal.
Console.Write("Input string in hexadecimal: ");
foreach (char c in inputString.ToCharArray())
{
Console.Write("0x{0:X2} ", (int)c);
}
Console.Write(twoNewLines);
// --------------------------------------------------------------------------
// Encode the input string.
Console.WriteLine("Encode the input string...");
numberOfEncodedBytes = ae.GetBytes(inputString, 0, inputString.Length,
encodedBytes, 0);
// Display the encoded bytes.
Console.WriteLine("Encoded bytes in hexadecimal ({0} bytes):\n",
numberOfEncodedBytes);
foreach (byte b in encodedBytes)
{
Console.Write("0x{0:X2} ", (int)b);
}
Console.Write(twoNewLines);
// --------------------------------------------------------------------------
// Replace the encoded byte sequences for the characters 'X' and 'Z' with the
// value 0xFF, which is outside the valid range of 0x00 to 0x7F for
// ASCIIEncoding. The resulting byte sequence is actually the beginning of
// this code example because it is the input to the decoder operation, and
// is equivalent to a corrupted or improperly encoded byte sequence.
encodedBytes[0] = 0xFF;
encodedBytes[2] = 0xFF;
Console.WriteLine("Display the corrupted byte sequence...");
Console.WriteLine("Encoded bytes in hexadecimal ({0} bytes):\n",
numberOfEncodedBytes);
foreach (byte b in encodedBytes)
{
Console.Write("0x{0:X2} ", (int)b);
}
Console.Write(twoNewLines);
// --------------------------------------------------------------------------
// Attempt to decode the encoded bytes. However, an exception is thrown
// before the byte sequence can be decoded.
Console.WriteLine("Compare the decoded bytes to the input string...");
try {
decodedString = ae.GetString(encodedBytes);
}
catch (DecoderFallbackException dfe)
{
Console.WriteLine(dfe);
Console.WriteLine("\n*** THE CODE EXAMPLE TERMINATES HERE AS INTENDED. ***");
return;
}
// This statement is never executed.
Console.WriteLine("This statement is never executed.");
}
}
/*
This code example produces the following results:
The name of the encoding is "us-ascii".
Input string (3 characters): "XYZ"
Input string in hexadecimal: 0x58 0x59 0x5A
Encode the input string...
Encoded bytes in hexadecimal (3 bytes):
0x58 0x59 0x5A
Display the corrupted byte sequence...
Encoded bytes in hexadecimal (3 bytes):
0xFF 0x59 0xFF
Compare the decoded bytes to the input string...
System.Text.DecoderFallbackException: Unable to translate bytes [FF] at index 0 from speci
fied code page to Unicode.
at System.Text.DecoderExceptionFallbackBuffer.Throw(Byte[] bytesUnknown, Int32 index)
at System.Text.DecoderExceptionFallbackBuffer.Fallback(Byte[] bytesUnknown, Int32 index
)
at System.Text.DecoderFallbackBuffer.InternalFallback(Byte[] bytes, Byte* pBytes)
at System.Text.ASCIIEncoding.GetCharCount(Byte* bytes, Int32 count, DecoderNLS decoder)
at System.String.CreateStringFromEncoding(Byte* bytes, Int32 byteLength, Encoding encod
ing)
at System.Text.ASCIIEncoding.GetString(Byte[] bytes, Int32 byteIndex, Int32 byteCount)
at System.Text.Encoding.GetString(Byte[] bytes)
at Sample.Main()
*** THE CODE EXAMPLE TERMINATES HERE AS INTENDED. ***
*/
' This example demonstrates the DecoderExceptionFallback class.
Imports System.Text
Class Sample
Public Shared Sub Main()
' Create an encoding, which is equivalent to calling the
' ASCIIEncoding class constructor.
' The DecoderExceptionFallback parameter specifies that an exception
' is thrown if a character cannot be encoded.
' An encoder exception fallback is also specified, but in this code
' example the encoding operation cannot fail.
Dim eef As New EncoderExceptionFallback()
Dim def As New DecoderExceptionFallback()
Dim ae As Encoding = Encoding.GetEncoding("us-ascii", eef, def)
Dim inputString As String = "XYZ"
Dim decodedString As String
Dim twoNewLines As String = vbCrLf & vbCrLf
Dim numberOfEncodedBytes As Integer = ae.GetByteCount(inputString)
' Counteract the compiler adding an extra element.
Dim encodedBytes(numberOfEncodedBytes - 1) As Byte
' --------------------------------------------------------------------------
Console.Clear()
' Display the name of the encoding.
Console.WriteLine("The name of the encoding is ""{0}""." & vbCrLf, ae.WebName)
' Display the input string in text.
Console.WriteLine("Input string ({0} characters): ""{1}""", inputString.Length, inputString)
' Display the input string in hexadecimal.
' Each element is converted to an integer with Convert.ToInt32.
Console.Write("Input string in hexadecimal: ")
Dim c As Char
For Each c In inputString.ToCharArray()
Console.Write("0x{0:X2} ", Convert.ToInt32(c))
Next c
Console.Write(twoNewLines)
' --------------------------------------------------------------------------
' Encode the input string.
Console.WriteLine("Encode the input string...")
numberOfEncodedBytes = ae.GetBytes(inputString, 0, inputString.Length, _
encodedBytes, 0)
' Display the encoded bytes.
' Each element is converted to an integer with Convert.ToInt32.
Console.WriteLine("Encoded bytes in hexadecimal ({0} bytes):" & vbCrLf, _
numberOfEncodedBytes)
Dim b As Byte
For Each b In encodedBytes
Console.Write("0x{0:X2} ", Convert.ToInt32(b))
Next b
Console.Write(twoNewLines)
' --------------------------------------------------------------------------
' Replace the encoded byte sequences for the characters 'X' and 'Z' with the
' value 0xFF, which is outside the valid range of 0x00 to 0x7F for
' ASCIIEncoding. The resulting byte sequence is actually the beginning of
' this code example because it is the input to the decoder operation, and
' is equivalent to a corrupted or improperly encoded byte sequence.
encodedBytes(0) = &HFF
encodedBytes(2) = &HFF
Console.WriteLine("Display the corrupted byte sequence...")
' Each element is converted to an integer with Convert.ToInt32.
Console.WriteLine("Encoded bytes in hexadecimal ({0} bytes):" & vbCrLf, _
numberOfEncodedBytes)
For Each b In encodedBytes
Console.Write("0x{0:X2} ", Convert.ToInt32(b))
Next b
Console.Write(twoNewLines)
' --------------------------------------------------------------------------
' Attempt to decode the encoded bytes. However, an exception is thrown
' before the byte sequence can be decoded.
Console.WriteLine("Compare the decoded bytes to the input string...")
Try
decodedString = ae.GetString(encodedBytes)
Catch dfe As DecoderFallbackException
Console.WriteLine(dfe)
Console.WriteLine(vbCrLf & _
"*** THE CODE EXAMPLE TERMINATES HERE AS INTENDED. ***")
Return
End Try
' This statement is never executed.
Console.WriteLine("This statement is never executed.")
End Sub
End Class
'
'This code example produces the following results:
'
'The name of the encoding is "us-ascii".
'
'Input string (3 characters): "XYZ"
'Input string in hexadecimal: 0x58 0x59 0x5A
'
'Encode the input string...
'Encoded bytes in hexadecimal (3 bytes):
'
'0x58 0x59 0x5A
'
'Display the corrupted byte sequence...
'Encoded bytes in hexadecimal (3 bytes):
'
'0xFF 0x59 0xFF
'
'Compare the decoded bytes to the input string...
'System.Text.DecoderFallbackException: Unable to translate bytes [FF] at index 0 from speci
'fied code page to Unicode.
' at System.Text.DecoderExceptionFallbackBuffer.Throw(Byte[] bytesUnknown, Int32 index)
' at System.Text.DecoderExceptionFallbackBuffer.Fallback(Byte[] bytesUnknown, Int32 index
')
' at System.Text.DecoderFallbackBuffer.InternalFallback(Byte[] bytes, Byte* pBytes)
' at System.Text.ASCIIEncoding.GetCharCount(Byte* bytes, Int32 count, DecoderNLS decoder)
'
' at System.String.CreateStringFromEncoding(Byte* bytes, Int32 byteLength, Encoding encod
'ing)
' at System.Text.ASCIIEncoding.GetString(Byte[] bytes, Int32 byteIndex, Int32 byteCount)
' at System.Text.Encoding.GetString(Byte[] bytes)
' at Sample.Main()
'
'*** THE CODE EXAMPLE TERMINATES HERE AS INTENDED. ***
'
'
Konstruktoren
| DecoderFallbackException() |
Initialisiert eine neue Instanz der DecoderFallbackException-Klasse. |
| DecoderFallbackException(String) |
Initialisiert eine neue Instanz der DecoderFallbackException-Klasse. Ein Parameter gibt die Fehlermeldung an. |
| DecoderFallbackException(String, Byte[], Int32) |
Initialisiert eine neue Instanz der DecoderFallbackException-Klasse. Parameter geben die Fehlermeldung, das decodierte Bytearray und den Index der Bytes an, die nicht decodiert werden können. |
| DecoderFallbackException(String, Exception) |
Initialisiert eine neue Instanz der DecoderFallbackException-Klasse. Parameter geben die Fehlermeldung und die innere Ausnahme an, die die Ausnahme verursacht hat. |
Eigenschaften
| BytesUnknown |
Ruft die Eingabebytefolge ab, die die Ausnahme verursachte. |
| Data |
Ruft eine Auflistung von Schlüssel-Wert-Paaren ab, die zusätzliche benutzerdefinierte Informationen zur Ausnahme bereitstellen. (Geerbt von Exception) |
| HelpLink |
Ruft einen Link zur Hilfedatei ab, die dieser Ausnahme zugeordnet ist, oder legt einen Link fest. (Geerbt von Exception) |
| HResult |
Ruft HRESULT ab oder legt HRESULT fest. Dies ist ein codierter Wert, der einer bestimmten Ausnahme zugeordnet ist. (Geerbt von Exception) |
| Index |
Ruft den Index in der Eingabebytefolge des Bytes ab, das die Ausnahme verursachte. |
| InnerException |
Ruft die Exception-Instanz ab, die die aktuelle Ausnahme verursacht hat. (Geerbt von Exception) |
| Message |
Ruft die Fehlermeldung und den Parameternamen oder nur die Fehlermeldung ab, wenn kein Parametername festgelegt ist. (Geerbt von ArgumentException) |
| ParamName |
Ruft den Namen des Parameters ab, der diese Ausnahme auslöst. (Geerbt von ArgumentException) |
| Source |
Gibt den Namen der Anwendung oder des Objekts zurück, die bzw. das den Fehler verursacht hat, oder legt diesen fest. (Geerbt von Exception) |
| StackTrace |
Ruft eine Zeichenfolgendarstellung der unmittelbaren Frames in der Aufrufliste ab. (Geerbt von Exception) |
| TargetSite |
Ruft die Methode ab, die die aktuelle Ausnahme auslöst. (Geerbt von Exception) |
Methoden
| Equals(Object) |
Bestimmt, ob das angegebene Objekt gleich dem aktuellen Objekt ist. (Geerbt von Object) |
| GetBaseException() |
Gibt beim Überschreiben in einer abgeleiteten Klasse eine Exception zurück, die die Grundursache für eine oder mehrere nachfolgende Ausnahmen ist. (Geerbt von Exception) |
| GetHashCode() |
Fungiert als Standardhashfunktion. (Geerbt von Object) |
| GetObjectData(SerializationInfo, StreamingContext) |
Legt das SerializationInfo-Objekt mit dem Parameternamen und zusätzlichen Informationen zur Ausnahme fest. (Geerbt von ArgumentException) |
| GetType() |
Ruft den Laufzeittyp der aktuellen Instanz ab. (Geerbt von Exception) |
| MemberwiseClone() |
Erstellt eine flache Kopie des aktuellen Object. (Geerbt von Object) |
| ToString() |
Erstellt eine Zeichenfolgendarstellung der aktuellen Ausnahme und gibt diese zurück. (Geerbt von Exception) |
Ereignisse
| SerializeObjectState |
Veraltet.
Tritt auf, wenn eine Ausnahme serialisiert wird, um ein Ausnahmezustandsobjekt mit serialisierten Daten über die Ausnahme zu erstellen. (Geerbt von Exception) |