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XmlReader.ReadValueChunkAsync(Char[], Int32, Int32) Method


Asynchronously reads large streams of text embedded in an XML document.

 virtual System::Threading::Tasks::Task<int> ^ ReadValueChunkAsync(cli::array <char> ^ buffer, int index, int count);
public virtual System.Threading.Tasks.Task<int> ReadValueChunkAsync (char[] buffer, int index, int count);
abstract member ReadValueChunkAsync : char[] * int * int -> System.Threading.Tasks.Task<int>
override this.ReadValueChunkAsync : char[] * int * int -> System.Threading.Tasks.Task<int>
Public Overridable Function ReadValueChunkAsync (buffer As Char(), index As Integer, count As Integer) As Task(Of Integer)



The array of characters that serves as the buffer to which the text contents are written. This value cannot be null.


The offset within the buffer where the XmlReader can start to copy the results.


The maximum number of characters to copy into the buffer. The actual number of characters copied is returned from this method.


The number of characters read into the buffer. The value zero is returned when there is no more text content.


An XmlReader 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." -or-

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


This is the asynchronous version of ReadValueChunk, with the same functionality. To use this method, you must set the Async flag to true.

This method stores in the task it returns all non-usage exceptions that the method's synchronous counterpart can throw. If an exception is stored into the returned task, that exception will be thrown when the task is awaited. Usage exceptions, such as ArgumentException, are still thrown synchronously. For the stored exceptions, see the exceptions thrown by ReadValueChunk(Char[], Int32, Int32).

Applies to

See also