UnicodeEncoding.GetCharCount Method (Byte[], Int32, Int32)

Calculates the number of characters produced by decoding a sequence of bytes from the specified byte array.

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

public override int GetCharCount(
	byte[] bytes,
	int index,
	int count


Type: System.Byte[]
The byte array containing the sequence of bytes to decode.
Type: System.Int32
The zero-based index of the first byte to decode.
Type: System.Int32
The number of bytes to decode.

Return Value

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


bytes is null (Nothing).


index or count is less than zero.


index and count do not denote a valid range in bytes.


The resulting number of bytes is greater than the maximum number that can be returned as an integer.


Error detection is enabled, and bytes contains an invalid sequence of bytes.


A fallback occurred (see Understanding Encodings for fuller explanation).

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

With error detection, an invalid sequence causes this method to throw a ArgumentException. Without error detection, invalid sequences are ignored, and no exception is thrown.

The following code example demonstrates how to use the GetCharCount method to return the number of characters produced by decoding a range of elements in a byte array using UnicodeEncoding.

using System;
using System.Text;

class Example
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
      Byte[] bytes = new Byte[] {
            85, 0, 110, 0, 105, 0, 99, 0, 111, 0, 100, 0, 101, 0

      UnicodeEncoding Unicode = new UnicodeEncoding();
      int charCount = Unicode.GetCharCount(bytes, 2, 8);
      outputBlock.Text += String.Format(
          "{0} characters needed to decode bytes.", charCount
      ) + "\n";


Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

Community Additions