I understand that using Perfmon.msc you can create a custom performance counter and by using counter log, you can write the counter value to a text file.
I also understand I can also use this programatically by creating a performance counter by using System.Diagnostics.PerformanceCounter, and get the counter value using NextValue() method.
Is there a programatical way to tell the PerformanceCounter object to write the log to a text file too (similar to Counter Log in perfmon.msc)?
In .NET you will have to sample the counter yourself and write the sampled value to a file. However, the Win32 API has functions to do what you want. For an example of the native API see Writing Performance Data to a Log File. You could try to use p/invoke to call the API.
May be this link will be helpfull.
By this link you can find .NET Framework analogs of Win32 Functions and Classes.
Using P/Invoke as suggested by another poster gave too much trouble. I suggest running logman from command line