Encoding.GetCharCount Method (Byte[])

July 28, 2014

When overridden in a derived class, calculates the number of characters produced by decoding all the bytes in the specified byte array.

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

public virtual int GetCharCount(
	byte[] bytes
)

Parameters

bytes
Type: System.Byte []
The byte array containing the sequence of bytes to decode.

Return Value

Type: System.Int32
The number of characters produced by decoding the specified sequence of bytes.

ExceptionCondition
ArgumentNullException

bytes is null.

DecoderFallbackException

A fallback occurred.

To calculate the exact array size required by GetChars to store the resulting characters, the application should use GetCharCount. To calculate the maximum array size, the application should use GetMaxCharCount. The GetCharCount method generally allocates less memory, while the GetMaxCharCount method generally executes faster.

For a discussion of programming considerations for use of this method, see the Encoding class description.

The following code example encodes a string into an array of bytes, and then decodes the bytes into an array of characters.


using System;
using System.Text;

public class Example
{
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      // Create two instances of UTF32Encoding: one with little-endian byte order and one with big-endian byte order.
      Encoding u32LE = Encoding.GetEncoding("utf-32");
      Encoding u32BE = Encoding.GetEncoding("utf-32BE");

      // Use a string containing the following characters:
      //    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)
      String myStr = "za\u0306\u01FD\u03B2";

      // Encode the string using the big-endian byte order.
      byte[] barrBE = new byte[u32BE.GetByteCount(myStr)];
      u32BE.GetBytes(myStr, 0, myStr.Length, barrBE, 0);

      // Encode the string using the little-endian byte order.
      byte[] barrLE = new byte[u32LE.GetByteCount(myStr)];
      u32LE.GetBytes(myStr, 0, myStr.Length, barrLE, 0);

      // Get the char counts, and decode the byte arrays.
      outputBlock.Text += "BE array with BE encoding : ";
      PrintCountsAndChars(outputBlock, barrBE, u32BE);
      outputBlock.Text += "LE array with LE encoding : ";
      PrintCountsAndChars(outputBlock, barrLE, u32LE);
   }

   public static void PrintCountsAndChars(System.Windows.Controls.TextBlock outputBlock, byte[] bytes, Encoding enc)
   {

      // Display the name of the encoding used.
      outputBlock.Text += String.Format("{0,-25} :", enc.ToString());

      // Display the exact character count.
      int iCC = enc.GetCharCount(bytes);
      outputBlock.Text += String.Format(" {0,-3}", iCC);

      // Display the maximum character count.
      int iMCC = enc.GetMaxCharCount(bytes.Length);
      outputBlock.Text += String.Format(" {0,-3} :", iMCC);

      // Decode the bytes and display the characters.
      char[] chars = enc.GetChars(bytes);
      outputBlock.Text += chars + "\n";
   }
}


/* 
This code produces the following output.

   BE array with BE encoding : System.Text.UTF32Encoding : 5   12  :zăǽβ
   LE array with LE encoding : System.Text.UTF32Encoding : 5   12  :zăǽβ

*/


Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Windows Phone

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