DecoderFallbackException Class
The exception that is thrown when a decoder fallback operation fails. This class cannot be inherited.
Assembly: mscorlib (in mscorlib.dll)
System::Exception
System::SystemException
System::ArgumentException
System.Text::DecoderFallbackException
| Name | Description | |
|---|---|---|
![]() | DecoderFallbackException() | Initializes a new instance of the DecoderFallbackException class. |
![]() | DecoderFallbackException(String^) | Initializes a new instance of the DecoderFallbackException class. A parameter specifies the error message. |
![]() | DecoderFallbackException(String^, array<Byte>^, Int32) | Initializes a new instance of the DecoderFallbackException class. Parameters specify the error message, the array of bytes being decoded, and the index of the byte that cannot be decoded. |
![]() | DecoderFallbackException(String^, Exception^) | Initializes a new instance of the DecoderFallbackException class. Parameters specify the error message and the inner exception that is the cause of this exception. |
| Name | Description | |
|---|---|---|
![]() | BytesUnknown | Gets the input byte sequence that caused the exception. |
![]() | 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.) |
![]() | Index | Gets the index position in the input byte sequence of the byte that caused the exception. |
![]() | InnerException | |
![]() | Message | Gets the error message and the parameter name, or only the error message if no parameter name is set.(Inherited from ArgumentException.) |
![]() | ParamName | Gets the name of the parameter that causes this exception.(Inherited from ArgumentException.) |
![]() | 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.) |
![]() | GetBaseException() | |
![]() | GetHashCode() | Serves as the default hash function. (Inherited from Object.) |
![]() | GetObjectData(SerializationInfo^, StreamingContext) | Sets the SerializationInfo object with the parameter name and additional exception information.(Inherited from ArgumentException.) |
![]() | GetType() | Gets the runtime type of the current instance.(Inherited from Exception.) |
![]() | ToString() | Creates and returns a string representation of the current exception.(Inherited from Exception.) |
The following code example demonstrates the DecoderExceptionFallback and DecoderFallbackException classes.
// 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. *** */
Available since 8
.NET Framework
Available since 2.0
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.

