How to get the method name and line number in Exception in ASP Core 5

Question

I want to get the method name and line number when an error occur, I am using Core 5.

        try
        {
           //My code
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Method Name / Line Number");
        }

Update:

I found a Solution like this:

_logger.LogError(ex, "\n=> ex Error: " + ex + "\n=> Action Name: " + ex.TargetSite.ReflectedType.Name + "\n=> Error Message: " + ex.Message + "\n=> Line Number: " + ex.LineNumber());

Answer 1

A simple call to ToString() on exception will give you the complete information needed. For example when we run the following code:

public static void Main()
{
    try
    {
        //my code
        throw new ArgumentException();
    }
    catch (Exception ex)
    {
        Console.WriteLine(ex.ToString());
    }
}

The output would be somewhat like:

System.ArgumentException: Value does not fall within the expected range.
   at ConsoleApp.Program.Main() in C:\Users\USER\source\Playground\ConsoleApp1\Program.cs:line 20

where Main() is the method name and 20 is the line number.

To get the format as required in question we can write a wrapper around the exception and fetch the line number from it:

using System;
using System.Reflection;

namespace ConsoleApp
{
    class Program
    {
        public static void Main()
        {
            try
            {
                //my code
                throw new ArgumentException();
            }
            catch (Exception ex)
            {
                Console.WriteLine(MethodBase.GetCurrentMethod().Name + "/" + GetLineNumber(ex));
            }
        }

        public static int GetLineNumber(Exception ex)
        {
            var lineNumber = 0;
            const string lineSearch = ":line ";
            var index = ex.StackTrace.LastIndexOf(lineSearch);
            if (index != -1)
            {
                var lineNumberText = ex.StackTrace.Substring(index + lineSearch.Length);
                if (int.TryParse(lineNumberText, out lineNumber))
                {
                }
            }
            return lineNumber;
        }
    }
}

Note: In the extract line method, we are fetching the top most exception. This comes in handy when we have a chain of exceptions in our stack trace.