Do __LINE__ __FILE__ equivalents exist in C#?

It is uglier, but you can do something like this in C# using the StackTrace and StackFrame classes:

StackTrace st = new StackTrace(new StackFrame(true));
Console.WriteLine(" Stack trace for current level: {0}", st.ToString());
StackFrame sf = st.GetFrame(0);
Console.WriteLine(" File: {0}", sf.GetFileName());
Console.WriteLine(" Method: {0}", sf.GetMethod().Name);
Console.WriteLine(" Line Number: {0}", sf.GetFileLineNumber());
Console.WriteLine(" Column Number: {0}", sf.GetFileColumnNumber());

Of course, this comes with some overhead.

Caller Information has been added to .NET 4.5. This will be compiled, a big improvement over having to examine the stack trace manually.

public void Log(string message,
        [CallerFilePath] string filePath = "",
        [CallerLineNumber] int lineNumber = 0)
{
    // Do logging
}

Simply call it in this manner. The compiler will fill in the file name and line number for you:

logger.Log("Hello!");

With Caller Information (introduced in .NET 4.5) you can create the equivalent of __LINE__ and __FILE__ in C#:

static int __LINE__([System.Runtime.CompilerServices.CallerLineNumber] int lineNumber = 0)
{
    return lineNumber;
}
static string __FILE__([System.Runtime.CompilerServices.CallerFilePath] string fileName = "")
{
    return fileName;
}

The only thing to remember is that these are functions and not compiler directives.

So for example:

MessageBox.Show("Line " + __LINE__() + " in " + __FILE__());

If you were to use this in practise then I'd suggest different names. I've used the C/C++ names just to make it clearer what they are returning, and something like CurrentLineNumber() and CurrentFileName() might be better names.

The advantage of using Caller Information over any solution that uses the StackTrace is that the line and file information is available for both debug and release.

The closest thing to those is the fact that you can create a StackTrace object and find out the name of the method at the top of the stack, so you can get close to the functionality of the __FUNCTION__ macro.

StackTrace stackTrace = new StackTrace();           
StackFrame[] stackFrames = stackTrace.GetFrames();  

foreach (StackFrame stackFrame in stackFrames)
    Console.WriteLine(stackFrame.GetMethod().Name);   

To reduce the cost of typing this out by hand, and also the runtime code, you can write a helper method:

[Conditional("Debug")]
public void LogMethodName()
{
    Trace.WriteLine("Entering:" + new StackTrace().GetFrame(1).GetMethod().Name);
}

Note how we get frame 1, as frame 0 would be LogMethodName itself. By marking it as Conditional("Debug") we ensure that the code is removed from release builds, which is one way to avoid the runtime cost where it may not be needed.