HttpListenerContext.AcceptWebSocketAsync Method (String)

.NET Framework (current version)

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Accept a WebSocket connection as an asynchronous operation.

Namespace:   System.Net
Assembly:  System (in System.dll)

public Task<HttpListenerWebSocketContext> AcceptWebSocketAsync(
	string subProtocol


Type: System.String

The supported WebSocket sub-protocol.

Return Value

Type: System.Threading.Tasks.Task<HttpListenerWebSocketContext>

Returns Task<TResult>.

The task object representing the asynchronous operation. The Result property on the task object returns an HttpListenerWebSocketContext object.

Exception Condition

subProtocol is an empty string


subProtocol contains illegal characters.


An error occurred when sending the response to complete the WebSocket handshake.

This operation will not block. The returned Task<TResult> object will complete after the WebSocket connection has been accepted.

The size of the receive buffer is 16,385 bytes. The WebSocket keep-alive interval is set to the default value of 30,000 (30 seconds).

.NET Framework
Available since 4.5
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