Declares members of test controls that are containers for another control.
Generally, you do not need to implement this interface. It is implemented by built-in test controls in the DevExpress.ExpressApp.EasyTest.WinAdapter.v19.1.dll and DevExpress.ExpressApp.EasyTest.WebAdapter.v19.1.dll assemblies. You can pass this interface as the ITestControl.GetInterface<T> generic parameter to access a test control that is a container. The complete list of interfaces that are implemented by built-in test controls is provided in the ITestControl topic.