WriteBase64Async Method
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XmlWriter.WriteBase64Async Method

[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]

Asynchronously encodes the specified binary bytes as Base64 and writes out the resulting text.

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

public virtual Task WriteBase64Async(
	byte[] buffer,
	int index,
	int count


Type: System.Byte []
Byte array to encode.
Type: System.Int32
The position in the buffer indicating the start of the bytes to write.
Type: System.Int32
The number of bytes to write.

Return Value

Type: System.Threading.Tasks.Task
The task that represents the asynchronous WriteBase64 operation.


An XmlWriter method was called before a previous asynchronous operation finished. In this case, InvalidOperationException is thrown with the message “An asynchronous operation is already in progress.”


An XmlWriter asynchronous method was called without setting the Async flag to true. In this case, InvalidOperationException is thrown with the message “Set XmlWriterSettings.Async to true if you want to use Async Methods.”

This is the asynchronous version of WriteBase64(Byte[], Int32, Int32), with the same functionality. To use this method, you must set the Async flag to true.

Windows Phone OS

Supported in: 8.1, 8.0

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