Yes.  There are multiple Microsoft .NET C# example 1-Wire projects.  The SDK containing the library of choice for .NET is the 1-Wire SDK for Windows.  The library to link a custom 1-Wire or iButton software project is the OneWireLinkLayer.dll.  If using a DS9490R USB-to-1-Wire adapter on a Windows PC, there is also a pre-requisite of downloading/installing the 1-Wire Drivers. For the DS9481R-3C7, the 1-Wire Drivers package is not required as it can use the .NET serial library to connect to serial port 1-Wire adapters.
The 1-Wire SDK, though, only has a couple of example programs.  The SDK gets downloaded as a zip file.  Simply unzip it and go to the .\Examples\Compact.NET\C# directory.  There, you will find two C# programs:
Get1WireAddresses simply performs a 1-Wire search and finds all the 1-Wire and/or iButton devices on the 1-Wire line and prints off their 1-Wire addresses (ROM numbers).  The OneWireIO program is a great utility that acts as a raw 1-Wire interface.  You can send and receive bytes (byte-by-byte) on the 1-Wire bus -- perfect for debugging 1-Wire transactions before implementing them in code.
Besides the above two programs with source, we also provide and maintain a GitHub repository with several example programs showing how to read/write different 1-Wire and iButton devices.  See below for a screenshot of the GitHub repository.  
The repository is called the 1-Wire SDK Examples and contains at least four .NET C# example programs (this number may change as new programs are released):
1. The ds2413_read_write program is a GUI program that exercises the switch states of the DS2413 1-Wire Dual-Channel Addressable Switch.
2. The ds2431_ds1972_read_write is a GUI program that reads and writes to each EEPROM memory device it finds.  The DS1972 iButton is actually just another packaged form of the DS2431.  It can write the entire memory of these devices with a single click.
3. The ds2502_read_write is a GUI program that reads/writes each EPROM device it finds.  It supports both the DS2502 and the iButton equivalent, DS1982.
4. Similar to number 3., the ds2505_read_write program exercises the DS2505 and the iButton equivalent, DS1985.