C# Driver Development

C# driver development?

You can not make kernel-mode device drivers in C# as the runtime can't be safely loaded into ring0 and operate as expected.

Additionally, C# doesn't create binaries suitable for loading as device drivers, particularly regarding entry points that drivers need to expose. The dependency on the runtime to jump in and analyze and JIT the binary during loading prohibits the direct access the driver subsystem needs to load the binary.

There is work underway, however, to lift some device drivers into user mode, you can see an interview here with Peter Wieland of the UDMF (User Mode Driver Framework) team.

User-mode drivers would be much more suited for managed work, but you'll have to google a bit to find out if C# and .NET will be directly supported. All I know is that kernel level drivers are not doable in only C#.

You can, however, probably make a C/C++ driver, and a C# service (or similar) and have the driver talk to the managed code, if you absolutely have to write a lot of code in C#.

Writing drivers in C#

Simply you can't. C# produces intermediate language that is interpreted by a virtual machine (.NET). All these stuff runs in user mode and WDM drivers run in kernel mode.

There is a DDK but it is not supported in VStudio either (but you can make a makefile project for compilation though).

Driver development is complex, prone to blue screen and requires a good understanding of C , kernel structures and mem manipulation. None of those skills are required for C# and .NET therefore there is a long and painful training path.

Why is C used for driver development rather than C#?

Because C# programs cannot run in kernel mode (Ring 0).

C# for Windows driver creation?

Please see: C# driver development?

Kernel level programming with C#

No. The CLR has user mode dependencies and can't be hosted in kernel mode.

That said, there are 2 more things to consider: one, that if you could satisfy the the CLR dependencies in some way, like providing your own implementations of Kernel32 and User32 and other user mode components, then it is probably at least possible. Two, the language itself could be used to output some other language, like x86 assembly, where this would be possible. You'd have to write the translator and provide BCL type analogs, yourself, though.

C# Test Driven Development

The test is failing because you haven't implemented the login method yet (see the NotImplementedException), this is by design in test driven development. You write enough code so that the method and test compile without implementing it, then you go to work implementing your method so that the test will pass.

Inject a login service into your TimeTable class:

public interface ILoginService
{
   bool Login(string username, string password);
}

public class TimeTable
{
   ILoginService _loginService;
   public TimeTable(ILoginService loginService)
   {
     _loginService = loginService;
   }

   public bool TimeTableLogin(string username, string password)
   {
      return loginService.Login(username, password);
   }
}

Then create a mock in your test project as an implementation for your login service. This version of the service is for testing only.

public MockLoginService : ILoginService
{
   public bool Login(string username, string password)
   {
     return (username == "Name" && password == "Password");
   }
}

Then in the test:

[TestMethod]
public void TestLoginMethodValid()
{
  MockLoginService mockLoginService = new MockLoginService();
  Timetable auth = new Timetable(mockLoginService);
  bool result = auth.TimetableLogin("Name", "Password"); 
  Assert.IsTrue(result);
}

Now you are testing the logic inside TimeTable.TimetableLogin and not the login service. Next you implement the real version of your ILoginService to be used in production and you can have confidence that TimeTable.TimetableLogin will perform as expected.

How to write driver for HID device in c# windows application

Writing a driver in .NET is more or less impossible (more importantly, getting .NET anywhere near the kernel is a bad idea; user mode drivers are an option (although only a recent one on Windows) - but it's still somewhat tricky). However, to use a HID device, you don't have to write a driver, as long as you only want to use the HID out of your application and not eg. Explorer.

A good start might be something like https://github.com/mikeobrien/HidLibrary.

C# Test Driven Development

The test is failing because you haven't implemented the login method yet (see the NotImplementedException), this is by design in test driven development. You write enough code so that the method and test compile without implementing it, then you go to work implementing your method so that the test will pass.

Inject a login service into your TimeTable class:

public interface ILoginService
{
   bool Login(string username, string password);
}

public class TimeTable
{
   ILoginService _loginService;
   public TimeTable(ILoginService loginService)
   {
     _loginService = loginService;
   }

   public bool TimeTableLogin(string username, string password)
   {
      return loginService.Login(username, password);
   }
}

Then create a mock in your test project as an implementation for your login service. This version of the service is for testing only.

public MockLoginService : ILoginService
{
   public bool Login(string username, string password)
   {
     return (username == "Name" && password == "Password");
   }
}

Then in the test:

[TestMethod]
public void TestLoginMethodValid()
{
  MockLoginService mockLoginService = new MockLoginService();
  Timetable auth = new Timetable(mockLoginService);
  bool result = auth.TimetableLogin("Name", "Password"); 
  Assert.IsTrue(result);
}

Now you are testing the logic inside TimeTable.TimetableLogin and not the login service. Next you implement the real version of your ILoginService to be used in production and you can have confidence that TimeTable.TimetableLogin will perform as expected.

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