Hi Yunis, welcome to the forum
This is the Dynamo forum, are you using C# with Dynamo?
That’s great if you are, please read How to get help on the Dynamo forums
Is it possible to add some more context about what you are trying to achieve with Dynamo or CivilConnection?
The most likely place to resolve C# issues with Revit is going to be here Revit API Forum on the Autodesk site where you get access to Jeremy Tammik who has an immense knowledge of the Revit API