Click here to Skip to main content
15,311,716 members
Articles / Web Development / ASP.NET
Posted 27 May 2002


100 bookmarked

Create Simple Error Log Files using ASP.NET and C#

Rate me:
Please Sign up or sign in to vote.
3.56/5 (44 votes)
27 May 20022 min read
An article on generating text based error log files

Sample Image

Picture 1. Sample error message

Sample Image

Picture 2. Sample error log file


This article demonstrates how to create a simple text based log file to log error messages with your own format using a C# class. Based on your needs, this class can modified and edited to create other log files, such as user activity log, user login time log, etc.

This class demonstrates the use of following namespaces:

  • System.IO
  • System.Text

The namespaces contain methods to create files in directories.

Installation Step

If you have downloaded the source code, you can follow these steps to install the project. You can then build and debug the code with VS.NET.

  1. Unzip the project source to \inetpub\wwwroot\CreateLogFiles directory
  2. Give the Logs directory -in the CreateLogFiles directory- full access permission, log files will be created in this directory
  3. Create new CreateLogFiles virtual site using your IIS MMC snap in, or Internet Services Manager
  4. If you are not using CreateLogFiles virtual site, edit the file CreateLogFiles.csproj.webinfo and set the URLPath to your virtual site name
  5. Double click CreateLogFiles.csproj with VS.NET and build the project to get the dll file in the bin directory
  6. Open your browser, browse to your project using http, in this case: http://localhost/CreateLogFiles/CreateLogFiles.aspx
  7. Try to fill the TextBox, if you have an error, you can see the errorlog was created in the Logs directory

Source Code

In this project, the main idea is to create a class, CreateLogFiles, that will create files in a specific directory from the web. This class uses two namespaces:

using System.IO;
using System.Text;

Before we make a function to create an error files, we have to declare some variables that will be used in our function. This is an example of variable declaration:

private string sLogFormat;
private string sErrorTime;

public CreateLogFiles()
    //sLogFormat used to create log files format :
    // dd/mm/yyyy hh:mm:ss AM/PM ==> Log Message
    sLogFormat = DateTime.Now.ToShortDateString().ToString()+" "+DateTime.Now.ToLongTimeString().ToString()+" ==> ";
    //this variable used to create log filename format "
    //for example filename : ErrorLogYYYYMMDD
    string sYear    = DateTime.Now.Year.ToString();
    string sMonth    = DateTime.Now.Month.ToString();
    string sDay    = DateTime.Now.Day.ToString();
    sErrorTime = sYear+sMonth+sDay;

and this is a function that will create error files. Please modify this function for your needs, or you can make other functions to create other log files :

public void ErrorLog(string sPathName, string sErrMsg)
    StreamWriter sw = new StreamWriter(sPathName+sErrorTime,true);
    sw.WriteLine(sLogFormat + sErrMsg);

To use this class, I create an example web form called: CreateLogFiles. A snapshot of this web form is shown above, picture 1. This is used to search a file in our directory. If the file exists, then no error log file is created, but when a file doesn't exist, it will create an error log file with the specific error message.

This is the code behind for this page. I call the ErrorLog function from our class when the Search button is clicked.

private void BtnFind_Click(object sender, System.EventArgs e)
        StreamReader sr = new StreamReader(this.TxtFilename.Text);
        Msg.Visible = true;
        Msg.Text = "File "+ this.TxtFilename.Text +" was found";
    catch(Exception ex)
        CreateLogFiles Err = new CreateLogFiles();
        Msg.Visible = true;
        Msg.Text = "Fatal error : "+ ex.Message + ", please find a complete error at ErrorLog file";

I am using try and catch to check automatically whether file exists or not. An error message gets automatically by the Exception method.

That's it. :-) You can view complete source code in the download file.


This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here


About the Author

Ali Ahmad H
Web Developer AliAhmadH
Indonesia Indonesia
Was born at Subang - West Java, Indonesia. Like all IT related information include programming and networking. Can be emailed at ali(at)

Comments and Discussions

Questionhow to display data from json file Pin
Member 1260922228-Jun-16 19:13
MemberMember 1260922228-Jun-16 19:13 
GeneralMy vote of 1 Pin
joginder-banger15-Jan-15 0:04
professionaljoginder-banger15-Jan-15 0:04 
QuestionNice article. Could this be done in VB? Pin
sudevsu8-Jan-15 4:06
Membersudevsu8-Jan-15 4:06 
When I tried to do this in VB.NET I get an error in first line

It says Type CreateLogFiles is not defined.

'Dim Err As CreateLogFiles = New CreateLogFiles()
            'Err.ErrorLog(Server.MapPath("Logs/ErrorLog"), ex.Message)
            'Msg.Visible = True
            'Msg.Text = "Fatal error : " + ex.Message + ", please find a complete error at ErrorLog file"

But I have this on same aspx page
<pre lang="vb">Public Sub CreateLogFiles()
        sLogFormat = DateTime.Now.ToShortDateString().ToString() + &quot; &quot; + DateTime.Now.ToLongTimeString().ToString() + &quot; ==&gt; &quot;
        &#39;this variable used to create log filename format &quot; //for example filename : ErrorLogYYYYMMDD
        Dim sYear As String = DateTime.Now.Year.ToString()
        Dim sMonth As String = DateTime.Now.Month.ToString()
        Dim sDay As String = DateTime.Now.Day.ToString()
        sErrorTime = sYear + sMonth + sDay
    End Sub</pre>

Please help me in solving this issue
Your help is much appreciated.
Happy Coding!

GeneralMy vote of 1 Pin
Akhil Mittal3-Jul-14 22:55
professionalAkhil Mittal3-Jul-14 22:55 
QuestionThanks Pin
BBBwex16-May-14 5:09
MemberBBBwex16-May-14 5:09 
QuestionNice Pin
Ganapathy A27-Aug-13 18:35
MemberGanapathy A27-Aug-13 18:35 
Questionthanks good Pin
rose lindo23-Apr-13 21:27
Memberrose lindo23-Apr-13 21:27 
GeneralMy vote of 2 Pin
hims05627-Nov-12 1:11
Memberhims05627-Nov-12 1:11 
GeneralThanks for Article Pin
Rajeshkumar Chavada8-Aug-12 1:20
MemberRajeshkumar Chavada8-Aug-12 1:20 
Questionconversion problem Pin
viji@sampathraj13-Dec-11 20:08
Memberviji@sampathraj13-Dec-11 20:08 
SuggestionPlease wrap disposable resources (StreamWriter & Reader) in using( ) blocks Pin
Damon Overboe26-Oct-11 4:39
MemberDamon Overboe26-Oct-11 4:39 
GeneralRe: Please wrap disposable resources (StreamWriter & Reader) in using( ) blocks Pin
Ashok A23-Apr-12 13:31
professionalAshok A23-Apr-12 13:31 
QuestionThank you! Pin
krembf5-Sep-11 11:33
Memberkrembf5-Sep-11 11:33 
Questionneed help to access Pin
madhuri from hyd1-Aug-11 2:22
Membermadhuri from hyd1-Aug-11 2:22 
AnswerRe: need help to access Pin
Ali Ahmad H1-Aug-11 16:41
MemberAli Ahmad H1-Aug-11 16:41 
GeneralThanks Pin
Lubna_0419-Apr-10 16:21
MemberLubna_0419-Apr-10 16:21 
GeneralThanks! Pin
Praveen Modi3-Apr-09 10:30
MemberPraveen Modi3-Apr-09 10:30 
GeneralRe: Thanks! Pin
Ali Ahmad H5-Apr-09 17:29
MemberAli Ahmad H5-Apr-09 17:29 
GeneralSmall enhancement - DirectoryNotFoundException Pin
jsytniak27-Apr-07 21:04
Memberjsytniak27-Apr-07 21:04 
Generalin case of multiple users Pin
VishalSharmaDev5-Oct-06 23:36
MemberVishalSharmaDev5-Oct-06 23:36 
GeneralERROR LOG Pin
RASHMIREKHA29-Mar-06 19:23
MemberRASHMIREKHA29-Mar-06 19:23 
GeneralERROR LOG Pin
RASHMIREKHA29-Mar-06 19:21
MemberRASHMIREKHA29-Mar-06 19:21 
QuestionEvent Log Security Exception Pin
Aanchal Naidu16-Dec-05 14:33
MemberAanchal Naidu16-Dec-05 14:33 
Generalsimple messege board Pin
Anonymous2-Oct-05 19:47
MemberAnonymous2-Oct-05 19:47 
GeneralRe: simple messege board Pin
Anonymous5-Oct-05 20:48
MemberAnonymous5-Oct-05 20:48 

General General    News News    Suggestion Suggestion    Question Question    Bug Bug    Answer Answer    Joke Joke    Praise Praise    Rant Rant    Admin Admin   

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.