.NET Framework 4.6 and 4.5
Occurs when the communication object first enters the opening state.
(in System.ServiceModel.Primitives.dll) System.ServiceModel
event EventHandler Opening
This event occurs when the communication object first begins to transition from the Created state into the Opened state, immediately after either the Open or BeginOpen method is invoked.
Supported in: 4.6, 4.5, 4, 3.5, 3.0
.NET Framework Client Profile
Supported in: 4, 3.5 SP1
.NET for Windows Phone apps
Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8
Portable Class Library
Supported in: Portable Class Library