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UTF8Encoding Constructor (Boolean, Boolean)

Initializes a new instance of the UTF8Encoding class. Parameters specify whether to provide a Unicode byte order mark and whether to throw an exception when an invalid encoding is detected.

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

public UTF8Encoding(
	bool encoderShouldEmitUTF8Identifier,
	bool throwOnInvalidBytes
)

Parameters

encoderShouldEmitUTF8Identifier
Type: System.Boolean
true to specify that a Unicode byte order mark is provided; otherwise, false.
throwOnInvalidBytes
Type: System.Boolean
true to specify that an exception be thrown when an invalid encoding is detected; otherwise, false.

If throwOnInvalidBytes is true, a method that detects an invalid byte sequence throws System.ArgumentException. Otherwise, the method does not throw an exception, and the invalid sequence is ignored.

NoteNote

For security reasons, your applications are recommended to use this constructor to create an instance of the UTF8Encoding class and turn on error detection by setting throwOnInvalidBytes to true.

The following example demonstrates how to create a new UTF8Encoding instance, specifying that a Unicode byte order mark prefix should not be emitted when encoding and an exception should be thrown when an invalid encoding is detected. The behavior of this constructor is compared to the default constructor for a UTF8Encoding, which does not throw an exception when an invalid encoding is detected.


using System;
using System.Text;

class UTF8EncodingExample {
    public static void Main() {
        UTF8Encoding utf8 = new UTF8Encoding();
        UTF8Encoding utf8ThrowException = new UTF8Encoding(false, true);

        // This array contains two high surrogates in a row (\uD801, \uD802).
        // A high surrogate should be followed by a low surrogate.
        Char[] chars = new Char[] {'a', 'b', 'c', '\uD801', '\uD802', 'd'};

        // The following method call will not throw an exception.
        Byte[] bytes = utf8.GetBytes(chars);
        ShowArray(bytes);

        try {
            // The following method call will throw an exception.
            bytes = utf8ThrowException.GetBytes(chars);
        } catch (Exception e) {
            Console.WriteLine("Exception raised. \nMessage: {0}", e.Message);
        }
    }

    public static void ShowArray(Array theArray) {
        foreach (Object o in theArray) {
            Console.Write("[{0}]", o);
        }
        Console.WriteLine();
    }
}


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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