Článek
11/18/2011

UTF8Encoding Constructor (Boolean)

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Initializes a new instance of the UTF8Encoding class. A parameter specifies whether to provide a Unicode byte order mark.

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

Syntax

'Declaration
Public Sub New ( _
    encoderShouldEmitUTF8Identifier As Boolean _
)

public UTF8Encoding(
    bool encoderShouldEmitUTF8Identifier
)

Parameters

encoderShouldEmitUTF8Identifier
Type: System.Boolean
true to specify that a Unicode byte order mark is provided; otherwise, false.

Remarks

This constructor creates an instance that does not throw an exception when an invalid encoding is detected.

Note:
For security reasons, your applications are recommended to enable error detection by using the constructor that accepts a throwOnInvalidBytes parameter and setting that parameter to true.

Examples

The following example demonstrates how to create a new UTF8Encoding instance, specifying that a Unicode byte order mark prefix should be emitted when encoding. The GetPreamble method returns the Unicode byte order mark prefix and displays it on the console. Notice that a UTF8Encoding created using the default constructor does not have a Unicode byte order mark prefix.

Imports System.Text

Class Example

   Public Shared Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
      Dim utf8 As New UTF8Encoding()
      Dim utf8EmitBOM As New UTF8Encoding(True)

      outputBlock.Text &= "utf8 preamble:" & vbCrLf
      ShowArray(outputBlock, utf8.GetPreamble())

      outputBlock.Text &= "utf8EmitBOM:" & vbCrLf
      ShowArray(outputBlock, utf8EmitBOM.GetPreamble())
   End Sub 'Main


   Public Shared Sub ShowArray(ByVal outputBlock As System.Windows.Controls.TextBlock, ByVal theArray As Array)
      Dim o As Object
      For Each o In theArray
         outputBlock.Text += String.Format("[{0}]", o)
      Next o
      outputBlock.Text &= vbCrLf
   End Sub 'ShowArray
End Class 'UTF8EncodingExample

using System;
using System.Text;

class Example
{
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      UTF8Encoding utf8 = new UTF8Encoding();
      UTF8Encoding utf8EmitBOM = new UTF8Encoding(true);

      outputBlock.Text += "utf8 preamble:" + "\n";
      ShowArray(outputBlock, utf8.GetPreamble());

      outputBlock.Text += "utf8EmitBOM:" + "\n";
      ShowArray(outputBlock, utf8EmitBOM.GetPreamble());
   }

   public static void ShowArray(System.Windows.Controls.TextBlock outputBlock, Array theArray)
   {
      foreach (Object o in theArray)
      {
         outputBlock.Text += String.Format("[{0}]", o);
      }
      outputBlock.Text += "\n";
   }
}

Version Information

Silverlight

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

Platforms

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

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