UdpClient.Active Property

Classes deriving from UdpClient can use this property to determine if a default remote host has been established. You can establish a default remote host by using the appropriate constructor or by calling the Connect method. If you do establish a default remote host, you cannot specify a remote host in your call to Send.

.NET Framework

.NET Framework Client Profile

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference