About the InfoPath XML interop assembly
The InfoPath XML interop assembly is provided to allow support for interoperability between managed code and the COM server exposed by Microsoft XML Core Services (MSXML) from external applications that automate InfoPath.
The .NET Programmability Support option in the InfoPath setup program installs three interop assemblies. Interop assemblies are .NET assemblies that act as a bridge between managed and unmanaged code, mapping COM object members to equivalent .NET managed members. One of those assemblies, Microsoft.Office.Interop.InfoPath.Xml.dll, provides the members of the Microsoft.Office.Interop.InfoPath.Xml namespace, which is used to work with members exposed by the COM server for Microsoft XML Core Services (MSXML) from external applications that automate InfoPath using managed code.
Note
The references to the Microsoft.Office.Interop.InfoPath.dll and Microsoft.Office.Interop.InfoPath.Xml.dll interop assemblies that are required for InfoPath external automation projects must be established manually. For more information on external automation, see External Automation Scenarios and Examples.