StringReader.ReadBlockAsync Method

Definition

Namespace:

System.IO

Assembly:

System.Runtime.dll

Overloads

ReadBlockAsync(Memory<Char>, CancellationToken)	Asynchronously reads all the characters from the input string starting at the current position and advances the current position to the end of the input string.
ReadBlockAsync(Char[], Int32, Int32)	Reads a specified maximum number of characters from the current string asynchronously and writes the data to a buffer, beginning at the specified index.

ReadBlockAsync(Memory<Char>, CancellationToken)

Source:

StringReader.cs

Asynchronously reads all the characters from the input string starting at the current position and advances the current position to the end of the input string.

public override System.Threading.Tasks.ValueTask<int> ReadBlockAsync (Memory<char> buffer, System.Threading.CancellationToken cancellationToken = default);

override this.ReadBlockAsync : Memory<char> * System.Threading.CancellationToken -> System.Threading.Tasks.ValueTask<int>

Public Overrides Function ReadBlockAsync (buffer As Memory(Of Char), Optional cancellationToken As CancellationToken = Nothing) As ValueTask(Of Integer)

Parameters

buffer

Memory<Char>

When this method returns, contains the characters read from the current source. If the total number of characters read is zero, the span remains unmodified.

cancellationToken

CancellationToken

The token to monitor for cancellation requests. The default value is None.

Returns

ValueTask<Int32>

A task representing the asynchronous read operation. The value of the TResult parameter contains the total number of characters read into the buffer.

Exceptions

OperationCanceledException

The cancellation token was canceled. This exception is stored into the returned task.

Remarks

ReadBlockAsync(Memory<Char>, CancellationToken) calls ReadBlock(Span<Char>) asynchronously, which in turn calls Read(Span<Char>) directly.

ReadBlockAsync(Char[], Int32, Int32)

Source:

StringReader.cs

Reads a specified maximum number of characters from the current string asynchronously and writes the data to a buffer, beginning at the specified index.

public:
 override System::Threading::Tasks::Task<int> ^ ReadBlockAsync(cli::array <char> ^ buffer, int index, int count);

public override System.Threading.Tasks.Task<int> ReadBlockAsync (char[] buffer, int index, int count);

override this.ReadBlockAsync : char[] * int * int -> System.Threading.Tasks.Task<int>

Public Overrides Function ReadBlockAsync (buffer As Char(), index As Integer, count As Integer) As Task(Of Integer)

Parameters

buffer

Char[]

When this method returns, contains the specified character array with the values between index and (index + count - 1) replaced by the characters read from the current source.

index

Int32

The position in buffer at which to begin writing.

count

Int32

The maximum number of characters to read. If the end of the string is reached before the specified number of characters is written into the buffer, the method returns.

Returns

Task<Int32>

A task that represents the asynchronous read operation. The value of the TResult parameter contains the total number of bytes read into the buffer. The result value can be less than the number of bytes requested if the number of bytes currently available is less than the requested number, or it can be 0 (zero) if the end of the string has been reached.

Exceptions

ArgumentNullException

buffer is null.

ArgumentOutOfRangeException

index or count is negative.

ArgumentException

The sum of index and count is larger than the buffer length.

ObjectDisposedException

The string reader has been disposed.

InvalidOperationException

The reader is currently in use by a previous read operation.

Remarks

The task does not complete until either the number of characters specified by the count parameter are read, or the end of the string has been reached.