EncoderFallbackException Class
The exception that is thrown when an encoder fallback operation fails. This class cannot be inherited.
Assembly: mscorlib (in mscorlib.dll)
System.Exception
System.SystemException
System.ArgumentException
System.Text.EncoderFallbackException
| Name | Description | |
|---|---|---|
![]() | EncoderFallbackException() | Initializes a new instance of the EncoderFallbackException class. |
![]() | EncoderFallbackException(String) | Initializes a new instance of the EncoderFallbackException class. A parameter specifies the error message. |
![]() | EncoderFallbackException(String, Exception) | Initializes a new instance of the EncoderFallbackException class. Parameters specify the error message and the inner exception that is the cause of this exception. |
| Name | Description | |
|---|---|---|
![]() | CharUnknown | Gets the input character that caused the exception. |
![]() | CharUnknownHigh | Gets the high component character of the surrogate pair that caused the exception. |
![]() | CharUnknownLow | Gets the low component character of the surrogate pair 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 buffer of the character 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.) |
![]() | IsUnknownSurrogate() | Indicates whether the input that caused the exception is a surrogate pair. |
![]() | ToString() | Creates and returns a string representation of the current exception.(Inherited from Exception.) |
The following code example demonstrates the EncoderExceptionFallback and EncoderFallbackException classes.
' This example demonstrates the EncoderExceptionFallback class. Imports System Imports System.Text Class Sample Public Shared Sub Main() ' Create an encoding, which is equivalent to calling the ' ASCIIEncoding class constructor. ' The EncoderExceptionFallback parameter causes an exception to ' be thrown when a character cannot be encoded. ' A decoder exception fallback is also specified, but it is not ' used because this example terminates during the encoding operation. Dim eef As New EncoderExceptionFallback() Dim def As New DecoderExceptionFallback() Dim ae As Encoding = Encoding.GetEncoding("us-ascii", eef, def) ' The input string consists of the Unicode characters LEFT POINTING ' DOUBLE ANGLE QUOTATION MARK (U+00AB), 'X' (U+0058), and RIGHT POINTING ' DOUBLE ANGLE QUOTATION MARK (U+00BB). ' The encoding can only encode characters in the US-ASCII range of U+0000 ' through U+007F. Consequently, the characters bracketing the 'X' character ' cause an exception. Dim inputString As String = "«X»" Dim twoNewLines As String = vbCrLf & vbCrLf Dim numberOfEncodedBytes As Integer = ae.GetMaxByteCount(inputString.Length) ' 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) ' -------------------------------------------------------------------------- ' Attempt to encode the input string. However, an exception is thrown before ' the input string can be encoded. Console.WriteLine("Encode the input string...") ' The code example terminates during the call to the GetBytes() method. Try numberOfEncodedBytes = ae.GetBytes(inputString, 0, inputString.Length, _ encodedBytes, 0) Catch e As EncoderFallbackException Console.WriteLine(e) 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 'Main End Class 'Sample ' 'This code example produces the following results: ' 'The name of the encoding is "us-ascii". ' 'Input string (3 characters): "X" 'Input string in hexadecimal: 0xAB 0x58 0xBB ' 'Encode the input string... 'System.Text.EncoderFallbackException: Unable to translate Unicode character \u00AB at inde 'x 0 to specified code page. ' at System.Text.EncoderExceptionFallbackBuffer.Fallback(Char charUnknown, Int32 index) ' at System.Text.EncoderFallbackBuffer.InternalFallback(Char ch, Char*& chars) ' at System.Text.ASCIIEncoding.GetBytes(Char* chars, Int32 charCount, Byte* bytes, Int32 'byteCount, EncoderNLS encoder) ' at System.Text.ASCIIEncoding.GetBytes(String chars, Int32 charIndex, Int32 charCount, B 'yte[] bytes, Int32 byteIndex) ' 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.

