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

Exception Condition

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 Character Encoding in the .NET Framework for fuller explanation)


DecoderFallback is set to DecoderExceptionFallback.

To calculate the exact array size required by GetChars to store the resulting characters, the application uses 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.

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 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 UnicodeEncodingExample {
    public static void Main() {
        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);
            "{0} characters needed to decode bytes.", charCount

Universal Windows Platform
Available since 4.5
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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