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Stream.EndRead(IAsyncResult) Method

Definition

Waits for the pending asynchronous read to complete. (Consider using ReadAsync(Byte[], Int32, Int32) instead.)

public virtual int EndRead (IAsyncResult asyncResult);

Parameters

asyncResult
IAsyncResult

The reference to the pending asynchronous request to finish.

Returns

The number of bytes read from the stream, between zero (0) and the number of bytes requested. ReadAsync returns zero (0) only if zero bytes were requested or if no more bytes will be available because it's at the end of the stream; otherwise, read operations do not complete until at least one byte is available. If zero bytes are requested, read operations may complete immediately or may not complete until at least one byte is available (but without consuming any data).

Exceptions

asyncResult is null.

A handle to the pending read operation is not available.

-or-

The pending operation does not support reading.

asyncResult did not originate from a BeginRead(Byte[], Int32, Int32, AsyncCallback, Object) method on the current stream.

The stream is closed or an internal error has occurred.

Remarks

In the .NET Framework 4 and earlier versions, you have to use methods such as BeginRead and EndRead to implement asynchronous I/O operations. These methods are still available in the .NET Framework 4.5 to support legacy code; however, the new async methods, such as ReadAsync, WriteAsync, CopyToAsync, and FlushAsync, help you implement asynchronous I/O operations more easily.

Call EndRead to determine how many bytes were read from the stream.

EndRead can be called once on every IAsyncResult from BeginRead.

This method blocks until the I/O operation has completed.

Applies to

Product Versions
.NET Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9
.NET Framework 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard 2.0, 2.1

See also