UnicodeEncoding::GetEncoder Method

Obtains an encoder that converts a sequence of Unicode characters into a UTF-16 encoded sequence of bytes.

Namespace:  System.Text
Assembly:  mscorlib (in mscorlib.dll)

[ComVisibleAttribute(false)]
public:
virtual Encoder^ GetEncoder() override

Return Value

Type: System.Text::Encoder
A Encoder object that converts a sequence of Unicode characters into a UTF-16 encoded sequence of bytes.

The Encoder::GetBytes method converts sequential blocks of characters into sequential blocks of bytes in a manner similar to the GetBytes method of this class. However, a Encoder object maintains state information between calls so that it can correctly encode character sequences that span blocks. The Encoder object also preserves trailing characters at the end of data blocks and uses the trailing characters in the next encoding operation. For example, a data block might end with an unmatched high surrogate, and the matching low surrogate might be in the next data block. Therefore, GetDecoder and GetEncoder are useful for network transmission and file operations, because those operations often deal with blocks of data instead of a complete data stream.

If error detection is enabled, that is, the throwOnInvalidBytes parameter of the constructor is set to true, error detection is also enabled in the Encoder object returned by this method. If error detection is enabled and an invalid sequence is encountered, the state of the encoder is undefined and processing must stop.

The following code example uses an encoder and a decoder to encode a string into an array of bytes, and then decode the bytes into an array of characters.

using namespace System;
using namespace System::Text;
int main()
{

   // Get an encoder and a decoder from UnicodeEncoding.
   UnicodeEncoding^ u16 = gcnew UnicodeEncoding( false,true,true );
   Encoder^ myEnc = u16->GetEncoder();
   Decoder^ myDec = u16->GetDecoder();

   // The characters to encode: 
   //    Latin Small Letter Z (U+007A) 
   //    Latin Small Letter A (U+0061) 
   //    Combining Breve (U+0306) 
   //    Latin Small Letter AE With Acute (U+01FD) 
   //    Greek Small Letter Beta (U+03B2) 
   array<Char>^myChars = gcnew array<Char>(5){
      L'z',L'a',L'\u0306',L'\u01FD',L'\u03B2'
   };
   Console::Write( "The original characters : " );
   Console::WriteLine( myChars );

   // Encode the character array. 
   int iBC = myEnc->GetByteCount( myChars, 0, myChars->Length, true );
   array<Byte>^myBytes = gcnew array<Byte>(iBC);
   myEnc->GetBytes( myChars, 0, myChars->Length, myBytes, 0, true );

   // Print the resulting bytes.
   Console::Write( "Using the encoder       : " );
   for ( int i = 0; i < myBytes->Length; i++ )
      Console::Write( "{0:X2} ", myBytes[ i ] );
   Console::WriteLine();

   // Decode the byte array back into an array of characters. 
   int iCC = myDec->GetCharCount( myBytes, 0, myBytes->Length, true );
   array<Char>^myDecodedChars = gcnew array<Char>(iCC);
   myDec->GetChars( myBytes, 0, myBytes->Length, myDecodedChars, 0, true );

   // Print the resulting characters.
   Console::Write( "Using the decoder       : " );
   Console::WriteLine( myDecodedChars );
}

/* 
This code produces the following output.  The question marks take the place of characters that cannot be displayed at the console.

The original characters : za??�
Using the encoder       : 7A 00 61 00 06 03 FD 01 B2 03
Using the decoder       : za??�

*/

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0, 2.0

Portable Class Library

Supported in: Portable Class Library

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8
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