System.IO.Stream.ReadAsync Method

Asynchronously reads a sequence of bytes from the current stream and advances the position within the stream by the number of bytes read.


public System.Threading.Tasks.Task<int> ReadAsync (byte[] buffer, int offset, int count)


The buffer to write the data into.
The byte offset in buffer at which to begin writing data from the stream.
The maximum number of bytes to read.


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 stream has been reached.


The Stream.ReadAsync(Byte[], int, int) method enables you to perform resource-intensive I/O operations without blocking the main thread. This performance consideration is particularly important in a win8_appname_long app or desktop_appname app where a time-consuming stream operation can block the UI thread and make your app appear as if it is not working. The async methods are used in conjunction with the async and await keywords in Visual Basic and C#.

Use the Stream.CanRead property to determine whether the current instance supports reading.


Namespace: System.IO
Assembly: mscorlib (in mscorlib.dll)
Assembly Versions: