TextReader.ReadAsync TextReader.ReadAsync TextReader.ReadAsync TextReader.ReadAsync Method

Definition

Overloads

ReadAsync(Char[], Int32, Int32) ReadAsync(Char[], Int32, Int32) ReadAsync(Char[], Int32, Int32) ReadAsync(Char[], Int32, Int32)

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

ReadAsync(Memory<Char>, CancellationToken) ReadAsync(Memory<Char>, CancellationToken)

ReadAsync(Char[], Int32, Int32) ReadAsync(Char[], Int32, Int32) ReadAsync(Char[], Int32, Int32) ReadAsync(Char[], Int32, Int32)

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

public:
 virtual System::Threading::Tasks::Task<int> ^ ReadAsync(cli::array <char> ^ buffer, int index, int count);
[System.Runtime.InteropServices.ComVisible(false)]
public virtual System.Threading.Tasks.Task<int> ReadAsync (char[] buffer, int index, int count);
abstract member ReadAsync : char[] * int * int -> System.Threading.Tasks.Task<int>
override this.ReadAsync : char[] * int * int -> System.Threading.Tasks.Task<int>
Public Overridable Function ReadAsync (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 Int32 Int32 Int32

The position in buffer at which to begin writing.

count
Int32 Int32 Int32 Int32

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

Returns

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 text has been reached.

Exceptions

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

Remarks

The task completes after either the number of characters specified by the count parameter are read or the end of the file is reached.

The TextReader class is an abstract class. Therefore, you do not instantiate it in your code. For an example of using the ReadAsync method, see the StreamReader.ReadAsync method.

See Also

ReadAsync(Memory<Char>, CancellationToken) ReadAsync(Memory<Char>, CancellationToken)

public virtual System.Threading.Tasks.ValueTask<int> ReadAsync (Memory<char> buffer, System.Threading.CancellationToken cancellationToken = null);
abstract member ReadAsync : Memory<char> * System.Threading.CancellationToken -> System.Threading.Tasks.ValueTask<int>
override this.ReadAsync : Memory<char> * System.Threading.CancellationToken -> System.Threading.Tasks.ValueTask<int>
Parameters
buffer
Memory<Char>
Returns

Applies to