In this overload, the buffer offset defaults to 0, and the number of bytes to send defaults to the size of the buffer. If you specify the SocketFlags.DontRoute flag as the socketflags parameter, the data you are sending will not be routed.

If you are using a connectionless protocol, you do not need to establish a default remote host with the Socket.Connect(System.Net.EndPoint) method prior to calling Socket.SendTo(Byte[], int, int, SocketFlags, System.Net.EndPoint). You only need to do this if you intend to call the Socket.Send(Byte[], int, SocketFlags) method. If you do call the Socket.Connect(System.Net.EndPoint) method prior to calling Socket.SendTo(Byte[], int, int, SocketFlags, System.Net.EndPoint), the remoteEP parameter will override the specified default remote host for that send operation only. You are also not required to call the Socket.Bind(System.Net.EndPoint) method, because the underlying service provider will assign the most appropriate local network address and port number. If you need to identify the assigned local network address and port number, you can use the Socket.LocalEndPoint property after the Socket.SendTo(Byte[], int, int, SocketFlags, System.Net.EndPoint) method successfully completes.

Although intended for connectionless protocols, Socket.SendTo(Byte[], int, int, SocketFlags, System.Net.EndPoint) also works with connection-oriented protocols. If you are using a connection-oriented protocol, you must first establish a remote host connection by calling the Socket.Connect(System.Net.EndPoint) method or accept an incoming connection request using the Socket.Accept method. If you do not establish or accept a remote host connection, Socket.SendTo(Byte[], int, int, SocketFlags, System.Net.EndPoint) will throw a System.Net.Sockets.SocketException. You can also establish a default remote host for a connectionless protocol prior to calling the Socket.SendTo(Byte[], int, int, SocketFlags, System.Net.EndPoint) method. In either of these cases, Socket.SendTo(Byte[], int, int, SocketFlags, System.Net.EndPoint) will ignore the remoteEP parameter and only send data to the connected or default remote host.

Blocking sockets will block until the requested all of the bytes in the buffer are sent. Since a nonblocking System.Net.Sockets.Socket completes immediately, it might not send all of the bytes in the buffer. It is your application's responsibility to keep track of the number of bytes sent and to retry the operation until the application sends all of the bytes in the buffer. There is also no guarantee that the data you send will appear on the network immediately. To increase network efficiency, the underlying system may delay transmission until a significant amount of out-going data is collected. A successful completion of the Socket.SendTo(Byte[], int, int, SocketFlags, System.Net.EndPoint) method means that the underlying system has had room to buffer your data for a network send.

If you are using a connectionless protocol in blocking mode, Socket.SendTo(Byte[], int, int, SocketFlags, System.Net.EndPoint) will block until the datagram is sent. If you want to send data to a broadcast address, you must first call the Socket.SetSocketOption(SocketOptionLevel, SocketOptionName, int) method and set the socket option to SocketOptionName.Broadcast. You must also be sure that the number of bytes sent does not exceed the maximum packet size of the underlying service provider. If it does, the datagram will not be sent and Socket.SendTo(Byte[], int, int, SocketFlags, System.Net.EndPoint) will throw a System.Net.Sockets.SocketException.

Namespace: System.Net.Sockets
Assembly: System (in System.dll)
Assembly Versions: 1.0.5000.0, 2.0.0.0, 4.0.0.0