logging exception in c#

I find that the easiest way to log exceptions in C# is to call the ToString() method:

try
{

}
catch (Exception ex)
{
    Console.WriteLine(ex.ToString());
}

This usually gives you all the information you need such as the error message and the stack trace, plus any extra exception specific context information. (however note that the stack trace will only show you source files and line numbers if you have your application compiled with debug information)

It is worth noting however that seeing a full stack trace can be fairly offputting for the user and so wherever possible you should try to handle exceptions and print out a more friendly error message.

On another note - you should replace your method WriteLogError with a fully featured logging framework (like Serilog) instead of trying to write your own.

Your logging method is not thread safe (your log file will probably end up with log messages being intermingled with each other) and also should definitely not call itself if you catch an exception - this will mean that any exceptions that occur whilst logging errors will probably cause a difficult to diagnose StackOverflow exception.

I could suggest how to fix those things, however you would be much better served just using a proper logging framework.

Just log ToString(). Not only will it give you the stack trace, but it'll also include the inner exceptions.

Also, when you deploy a release build of your code to a production environment for instance, don't forget to include the .pdb files in the release package. You need that file to get the line number of the code that excepted (see How much information do pdb files contain? (C# / .NET))