ConfigurationElementCollection.BaseAdd Method (ConfigurationElement, Boolean)
Adds a configuration element to the configuration element collection.
Assembly: System.Configuration (in System.Configuration.dll)
An element is considered a duplicate only if the keys are identical but the values are different. Elements with identical keys and values are accepted silently because the elements do not compete. However, an element with an identical key but a different value cannot be added because there is no logic to determine which of the competing values should be honored.
Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.