Article
11/18/2011

XmlReader.ReadContentAsBase64 Method

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

Reads the content and returns the Base64 decoded binary bytes.

Namespace: System.Xml
Assembly: System.Xml (in System.Xml.dll)

Syntax

'Declaration
Public Overridable Function ReadContentAsBase64 ( _
    buffer As Byte(), _
    index As Integer, _
    count As Integer _
) As Integer

public virtual int ReadContentAsBase64(
    byte[] buffer,
    int index,
    int count
)

Parameters

buffer
Type: array<System.Byte[]
The buffer into which to copy the resulting text. This value cannot be nulla null reference (Nothing in Visual Basic).

index
Type: System.Int32
The offset into the buffer where to start copying the result.

count
Type: System.Int32
The maximum number of bytes to copy into the buffer. The actual number of bytes copied is returned from this method.

Return Value

Type: System.Int32
The number of bytes written to the buffer.

Exceptions

Exception	Condition
ArgumentNullException	The buffer value is nulla null reference (Nothing in Visual Basic).
InvalidOperationException	ReadContentAsBase64 is not supported on the current node.
ArgumentOutOfRangeException	The index into the buffer or index + count is larger than the allocated buffer size.
NotSupportedException	The XmlReader implementation does not support this method.

Remarks

This method streams the content, decodes the Base64 content, and returns the decoded binary bytes (for example, an inline Base64 encoded GIF image) into the buffer. This method can be called successively to read large streams of embedded text. For more information, see RFC 1521, "MIME (Multipurpose Internet Mail Extensions) Part One: Mechanisms for Specifying and Describing the Format of Internet Message Bodies". You can obtain RFCs from the Request for Comments Web site.

Note:
You should not access any of the reader properties between calls to the ReadContentAsBase64 method until the method returns the value 0.

This method has the following behavior:

ReadContentAsBase64 returns the value 0 when it has reached the end of the byte stream it was operating on. The reader is positioned on the first non-content node.
If you ask for fewer, or the exact number of, bytes than are left in the stream the reader remains in its current position.
ReadContentAsBase64 is not supported on the following XML node types: Element, XmlDeclaration, None, Document, DocumentType, Notation, Entity, DocumentFragment.

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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