How to create a log error file in ASP.NET Programming Language?

using System; 
using System.Collections.Generic; 
using System.IO; 
using System.Linq; 
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Text; 
using System.Threading.Tasks; 
using System.Globalization;
public partial class _Defaut:System.Web.UI.page
{
protect void page_load(object sender,EventArgs e)
{
try{
var i=10;
var j=0;
var result= i/j;
Responce.Write(result);
}
catch(Exception e){
lblMessage.Text=“Exception generated! Plz check your Log Error File”;
createLogErrorFile(e.ToString());
}
}
private void createLogErrorFile(String errMessage)
{try{
string path=”~/”+DateTime.ToDay.ToString(“dd-mm-yy”)+”.txt”;
if(!File.Exists(System.Web.HttpContext.Current.Server.MathPath(path))
{
File.create(System.Web.HttpContext.Current.Server.MathPath(path)).close();
}
Using(StreamWriter w= File.AppenedText(System.Web.HttpContext.Current.Server.MathPath(path)))
w.WriteLine(“|n |n Log Entry : “);
w.WriteLine(“{0}”, DateTime.Now.ToString(CultureInfo.InvariantCulture));
String err=”Error in : “+System.Web.HttpContext.Current.Request.Url.ToString()+”|n |n Error Message : ”+ errMessage;
w.WriteLine(err);
W.WriteLine(“===========================================”);
w.Flush();
w.close();
}
catch{
throw;
}
}
}