Error-Handling Class and Logging

Question

I am relatively new to C# and would like to see if what I have been using for my exception handling, message and logging is along industry standards. I have created a simple class for the Error Handler and for the logging I use Log4Net. After reading Clean Code, I was thinking about separating DisplayMessage into 2 different procedures for the message and logging. The log file is usually written to a file server so multiple users can access it; I have enabled MinimalLock for this purpose. For my example, I have changed the log path to C:\Temp\. An example of a project I use the Error Handler class and logging in is on GitHub. For reference, I am using Visual Studio 2017 Community.

---

ErrorHandler.cs

using System;
using System.Windows.Forms;
using log4net;

[assembly: log4net.Config.XmlConfigurator(Watch = true)]

/// <summary> 
/// Used to handle exceptions
/// </summary>
public class ErrorHandler
{
    private static readonly ILog log = LogManager.GetLogger(typeof(ErrorHandler));

    /// <summary> 
    /// Used to produce an error message and create a log record
    /// <example>
    /// <code lang="C#">
    /// ErrorHandler.DisplayMessage(ex);
    /// </code>
    /// </example> 
    /// </summary>
    /// <param name="ex">Represents errors that occur during application execution.</param>
    /// <remarks></remarks>
    public static void DisplayMessage(Exception ex)
    {
        System.Diagnostics.StackFrame sf = new System.Diagnostics.StackFrame(1);
        System.Reflection.MethodBase caller = sf.GetMethod();
        string currentProcedure = (caller.Name).Trim();
        string errorMessageDescription = ex.ToString();
        errorMessageDescription = System.Text.RegularExpressions.Regex.Replace(errorMessageDescription, @"\r\n+", " "); //the carriage returns were messing up my log file
        string msg = "Contact your system administrator. A record has been created in the log file." + Environment.NewLine;
        msg += "Procedure: " + currentProcedure + Environment.NewLine;
        msg += "Description: " + ex.ToString() + Environment.NewLine;
        log.Error("[PROCEDURE]=|" + currentProcedure + "|[USER NAME]=|" + Environment.UserName + "|[MACHINE NAME]=|" + Environment.MachineName + "|[DESCRIPTION]=|" + errorMessageDescription);
        MessageBox.Show(msg, "Unexpected Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
    }

}

Usage Example:

/// <summary> 
/// Return the count of items in a delimited list
/// </summary>
/// <param name="valueList">Represents the list of values in a string </param>
/// <param name="delimiter">Represents the list delimiter </param>
/// <returns>the number of values in a delimited string</returns>
public int GetListItemCount(string valueList, string delimiter)
{
    try
    {
        string[] comboList = valueList.Split((delimiter).ToCharArray());
        return comboList.GetUpperBound(0) + 1;

    }
    catch (Exception ex)
    {
        ErrorHandler.DisplayMessage(ex);
        return 0;
    }
}

---

Log4Net

app.config

<log4net>
    <appender name="ConsoleAppender" type="log4net.Appender.ConsoleAppender">
        <layout type="log4net.Layout.PatternLayout">
            <conversionPattern value="%date [%thread] %-5level %logger [%ndc] - %message%newline"/>
        </layout>
    </appender>
    <appender name="FileAppender" type="log4net.Appender.FileAppender">
        <file value="C:\Temp\MyLogFile.log"/>
        <appendToFile value="true"/>
        <lockingModel type="log4net.Appender.FileAppender+MinimalLock"/>
        <layout type="log4net.Layout.PatternLayout">
            <conversionPattern value="%date|%-5level|%message%newline"/>
        </layout>
    </appender>
    <root>
        <level value="ALL"/>
        <appender-ref ref="FileAppender"/>
    </root>
</log4net>

Answer 1

I'm not familiar with log4net, so I will focus on the code itself.

Here is a list of what could be improved:

• --- Style ---
• ErrorHandler should be a static class to prevent newing up an instance of it
• Lack of using namespace: Generally, you should declare all of them, unless:
  • there is an conflic in which case you can alias it: using A = Some.Namespace.A
  • a namespace is particularly noisy and is polluting the intellisense

• Lack of var: Using the type name or the full name can make the code difficult to scan through. It is more difficult to locate a variable when they are not aligned. For the most part, the right hand side assignment should give enough of hint.

  System.Diagnostics.StackFrame sf = new System.Diagnostics.StackFrame(1);
  System.Reflection.MethodBase caller = sf.GetMethod();
  string currentProcedure = (caller.Name).Trim();
  // --- for comparison
  var sf = new System.Diagnostics.StackFrame(1);
  var caller = sf.GetMethod();
  var currentProcedure = (caller.Name).Trim();
  

• Lack of "spacing": Nobody likes reading a wall of text, and a wall of code is no better. You can divide the logical blocks of your code with some empty lines: (Think of them as paragraphs)

  // gather context
  var sf = new System.Diagnostics.StackFrame(1);
  var caller = sf.GetMethod();
  
  // format message
  var currentProcedure = (caller.Name).Trim();
  var errorMessageDescription = ex.ToString();
  errorMessageDescription = System.Text.RegularExpressions.Regex.Replace(errorMessageDescription, @"\r\n+", " "); //the carriage returns were messing up my log file
  var msg = "Contact your system administrator. A record has been created in the log file." + Environment.NewLine;
  msg += "Procedure: " + currentProcedure + Environment.NewLine;
  msg += "Description: " + ex.ToString() + Environment.NewLine;
  
  // handle exception
  log.Error("[PROCEDURE]=|" + currentProcedure + "|[USER NAME]=|" + Environment.UserName + "|[MACHINE NAME]=|" + Environment.MachineName + "|[DESCRIPTION]=|" + errorMessageDescription);
  MessageBox.Show(msg, "Unexpected Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
  

• Use of unnecessary parenthesis that doesn't highlight order of operation:

  string currentProcedure = (caller.Name).Trim();
  string[] comboList = valueList.Split((delimiter).ToCharArray());
  

• --- code ---

  string[] comboList = valueList.Split((delimiter).ToCharArray());
  return comboList.GetUpperBound(0) + 1;
  

  You can simply return comboList.Length here.

   /// <param name="delimiter">Represents the list delimiter </param>
   string[] comboList = valueList.Split((delimiter).ToCharArray());
  

  You are using it as multiple delimiters, and not just one. The name should reflect that.

   /// <returns>the number of values in a delimited string</returns>
  

  The return of value 0 in error handling should be documented in the <returns> or <remarks> tag.

---

public static class ErrorHandler
{
    public static void DisplayMessage(Exception ex)
    {
        var sf = new System.Diagnostics.StackFrame(1);
        var caller = sf.GetMethod();
        var currentProcedure = caller.Name.Trim();

        var logMessage = string.Concat(new Dictionary<string, string>
        {
            ["PROCEDURE"] = currentProcedure,
            ["USER NAME"] = Environment.UserName,
            ["MACHINE NAME"] = Environment.MachineName,
            ["DESCRIPTION"] = ex.ToString().Replace("\r\n", " "), // the carriage returns were messing up my log file
        }.Select(x => $"[{x.Key}]=|{x.Value}|"));
        log.Error(logMessage);

        // pick one:
        var userMessage = new StringBuilder()
            .AppendLine("Contact your system administrator. A record has been created in the log file.")
            .AppendLine("Procedure: " + currentProcedure)
            .AppendLine("Description: " + ex.ToString())
            .ToString();
        var userMessage = string.Join(Environment.NewLine,
            "Contact your system administrator. A record has been created in the log file.",
            "Procedure: " + currentProcedure,
            "Description: " + ex.ToString(),
        ) + Environment.NewLine;
        MessageBox.Show(userMessage, "Unexpected Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
    }
}