Decodes Base64 and returns the decoded binary bytes.
(in System.Xml.dll)
Visual Basic (Declaration)
Public Function ReadBase64 ( _
array As Byte(), _
offset As Integer, _
len As Integer _
) As Integer
Dim instance As XmlTextReader
Dim array As Byte()
Dim offset As Integer
Dim len As Integer
Dim returnValue As Integer
returnValue = instance.ReadBase64(array, _
offset, len)
public int ReadBase64(
byte[] array,
int offset,
int len
)
public:
int ReadBase64(
array<unsigned char>^ array,
int offset,
int len
)
public function ReadBase64(
array : byte[],
offset : int,
len : int
) : int
Parameters
- array
- Type: array<System..::.Byte>[]()[]
The array of characters that serves as the buffer to which the text contents are written.
- offset
- Type: System..::.Int32
The zero-based index into the array specifying where the method can begin to write to the buffer.
- len
- Type: System..::.Int32
The number of bytes to write into the buffer.
.gif) Note: |
|---|
In the .NET Framework version 2.0 release, the recommended practice is to create XmlReader instances using the XmlReader..::.Create method. This allows you to take full advantage of the new features introduced in this release. For more information, see Creating XML Readers. |
Like ReadChars, this method can be called successively to read large streams of embedded text. It decodes Base64 content and returns the decoded binary bytes (for example, an inline Base64 encoded GIF image) into the buffer. See RFC 1521. (You can obtain RFCs from the Request for Comments Web site at http://www.rfc-editor.org)
The following example reads a file containing Base64 and BinHex data.
Option Explicit
Option Strict
Imports System
Imports System.IO
Imports System.Xml
Imports Microsoft.VisualBasic
Public Class Sample
Private Const filename As String = "binary.xml"
Public Shared Sub Main()
Dim reader As XmlTextReader = Nothing
Dim i As Integer
Try
reader = New XmlTextReader(filename)
reader.WhitespaceHandling = WhitespaceHandling.None
' Read the file. Stop at the Base64 element.
While reader.Read()
If "Base64" = reader.Name Then
Exit While
End If
End While
' Read the Base64 data. Write the decoded
' bytes to the console.
Console.WriteLine("Reading base64... ")
Dim base64len As Integer = 0
Dim base64(1000) As Byte
Do
base64len = reader.ReadBase64(base64, 0, 50)
For i = 0 To base64len - 1
Console.Write(base64(i))
Next i
Loop While (reader.Name = "Base64")
' Read the BinHex data. Write the decoded
' bytes to the console.
Console.WriteLine(ControlChars.CrLf & "Reading binhex....")
Dim binhexlen As Integer = 0
Dim binhex(1000) As Byte
binhexlen = reader.ReadBinHex(binhex, 0, 50)
Do
binhexlen = reader.ReadBinHex(binhex, 0, 50)
For i = 0 To binhexlen - 1
Console.Write(binhex(i))
Next i
Loop While (reader.Name = "BinHex")
Finally
Console.WriteLine()
Console.WriteLine("Processing of the file {0} complete.", filename)
If Not (reader Is Nothing) Then
reader.Close()
End If
End Try
End Sub 'Main
End Class 'Sample
using System;
using System.IO;
using System.Xml;
public class Sample {
private const string filename = "binary.xml";
public static void Main() {
XmlTextReader reader = null;
try {
reader = new XmlTextReader(filename);
reader.WhitespaceHandling = WhitespaceHandling.None;
// Read the file. Stop at the Base64 element.
while (reader.Read()) {
if ("Base64" == reader.Name) break;
}
// Read the Base64 data. Write the decoded
// bytes to the console.
Console.WriteLine("Reading Base64... ");
int base64len = 0;
byte[] base64 = new byte[1000];
do {
base64len = reader.ReadBase64(base64, 0, 50);
for (int i=0; i < base64len; i++) Console.Write(base64[i]);
} while (reader.Name == "Base64");
// Read the BinHex data. Write the decoded
// bytes to the console.
Console.WriteLine("\r\nReading BinHex...");
int binhexlen = 0;
byte[] binhex = new byte[1000];
do {
binhexlen = reader.ReadBinHex(binhex, 0, 50);
for (int i=0; i < binhexlen; i++) Console.Write(binhex[i]);
} while (reader.Name == "BinHex");
}
finally {
Console.WriteLine();
Console.WriteLine("Processing of the file {0} complete.", filename);
if (reader != null)
reader.Close();
}
}
}
#using <System.Xml.dll>
using namespace System;
using namespace System::IO;
using namespace System::Xml;
int main()
{
XmlTextReader^ reader = nullptr;
String^ filename = "binary.xml";
try
{
reader = gcnew XmlTextReader( filename );
reader->WhitespaceHandling = WhitespaceHandling::None;
// Read the file. Stop at the Base64 element.
while ( reader->Read() )
{
if ( "Base64" == reader->Name )
break;
}
// Read the Base64 data. Write the decoded
// bytes to the console.
Console::WriteLine( "Reading Base64... " );
int base64len = 0;
array<Byte>^base64 = gcnew array<Byte>(1000);
do
{
base64len = reader->ReadBase64( base64, 0, 50 );
for ( int i = 0; i < base64len; i++ )
Console::Write( base64[ i ] );
}
while ( reader->Name->Equals( "Base64" ) );
// Read the BinHex data. Write the decoded
// bytes to the console.
Console::WriteLine( "\r\nReading BinHex..." );
int binhexlen = 0;
array<Byte>^binhex = gcnew array<Byte>(1000);
do
{
binhexlen = reader->ReadBinHex( binhex, 0, 50 );
for ( int i = 0; i < binhexlen; i++ )
Console::Write( binhex[ i ] );
}
while ( reader->Name->Equals( "BinHex" ) );
}
finally
{
Console::WriteLine();
Console::WriteLine( "Processing of the file {0} complete.", filename );
if ( reader != nullptr )
reader->Close();
}
}
#using <mscorlib.dll>
#using <System.Xml.dll>
using namespace System;
using namespace System::IO;
using namespace System::Xml;
int main() {
XmlTextReader* reader = 0;
String* filename = S"binary.xml";
try {
reader = new XmlTextReader(filename);
reader->WhitespaceHandling = WhitespaceHandling::None;
// Read the file. Stop at the Base64 element.
while (reader->Read()) {
if (S"Base64"->Equals(reader->Name)) break;
}
// Read the Base64 data. Write the decoded
// bytes to the console.
Console::WriteLine(S"Reading Base64... ");
int base64len = 0;
Byte base64[] = new Byte[1000];
do {
base64len = reader->ReadBase64(base64, 0, 50);
for (int i=0; i < base64len; i++) Console::Write(base64[i]);
} while (reader->Name->Equals(S"Base64"));
// Read the BinHex data. Write the decoded
// bytes to the console.
Console::WriteLine(S"\r\nReading BinHex...");
int binhexlen = 0;
Byte binhex[] = new Byte[1000];
do {
binhexlen = reader->ReadBinHex(binhex, 0, 50);
for (int i=0; i < binhexlen; i++) Console::Write(binhex[i]);
} while (reader->Name->Equals(S"BinHex"));
}
__finally {
Console::WriteLine();
Console::WriteLine(S"Processing of the file {0} complete.",filename);
if (reader != 0)
reader->Close();
}
}
The sample uses the file binary.xml
<data>
<!-- sample data for base64 and binhex -->
<Base64>AAECAwQFBgcICQoLDA0ODxAREhMUFRYXGBkaGxwdHh8gISIjJCUmJygpKissLS
4vMDEyMzQ1Njc4OTo7PD0+P0BBQkNERUZHSElKS0xNTk9QUVJTVFVWV1hZWltcXV5fYGFi
Y2RlZmdoaWprbG1ub3BxcnN0dXZ3eHl6e3x9fn+AgYKDhIWGh4iJiouMjY6PkJGSk5SVlp
eYmZqbnJ2en6ChoqOkpaanqKmqq6ytrq+wsbKztLW2t7i5uru8vb6/wMHCw8TFxsfIycrL
zM3Oz9DR0tPU1dbX2Nna29zd3t/g4eLj5OXm5+jp6uvs7e7v8PHy8/T19vf4+fr7/P3+/w
==</Base64>
<BinHex>000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E
1F202122232425262728292A2B2C2D2E2F303132333435363738393A3B3C3D3E3F4041
42434445464748494A4B4C4D4E4F505152535455565758595A5B5C5D5E5F6061626364
65666768696A6B6C6D6E6F707172737475767778797A7B7C7D7E7F8081828384858687
88898A8B8C8D8E8F909192939495969798999A9B9C9D9E9FA0A1A2A3A4A5A6A7A8A9AA
ABACADAEAFB0B1B2B3B4B5B6B7B8B9BABBBCBDBEBFC0C1C2C3C4C5C6C7C8C9CACBCCCD
CECFD0D1D2D3D4D5D6D7D8D9DADBDCDDDEDFE0E1E2E3E4E5E6E7E8E9EAEBECEDEEEFF0
F1F2F3F4F5F6F7F8F9FAFBFCFDFEFF</BinHex>
</data>
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
.NET Framework
Supported in: 3.5, 3.0, 2.0, 1.1, 1.0
.NET Compact Framework
Supported in: 3.5, 2.0, 1.0
XNA Framework
Supported in: 3.0, 2.0, 1.0
Reference
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