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Automatic Error Handling

, 17 Mar 2008
Handle web and WinForms exceptions automatically.
using System;
using System.Configuration;
using System.Collections.Specialized;
using System.IO;

//
// processes custom .config section as follows:
//
// <configSections>    
//	    <section name="UnhandledException" type="System.Configuration.NameValueSectionHandler, System, 
//        Version=1.0.5000.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />
// </configSections>
//
// <!-- settings for UnhandledExceptionManager -->
//	<UnhandledException>
//		<add key="ContactInfo" value="Ima Testguy at 123-555-1212" />
//		<add key="IgnoreDebug" value="False" />
//		<add key="IgnoreRegex" value="get_aspx_ver\.aspx" />
//		<add key="EmailTo" value="me@mydomain.com" />
//	</UnhandledException>   
//
// Complete configuration options are..
//  
//  <!-- Handler defaults -->
//  <add key="AppName" value="" />
//  <add key="ContactInfo" value="" />
//  <add key="EmailTo" value="" />
//  <add key="LogToEventLog" value="False" />
//  <add key="LogToFile" value="True" />
//  <add key="LogToEmail" value="True" />
//  <add key="LogToUI" value="True" />
//	 <add key="PathLogFile" value="" />
//  <add key="IgnoreRegex" value="" />
//  <add key="IgnoreDebug" value="True" />
//  <add key="WhatHappened" value="There was an unexpected error in this website. This may be due to a programming bug." />
//  <add key="HowUserAffected" value="The current page will not load." />
//  <add key="WhatUserCanDo" value="Close your browser, navigate back to this website, and try repeating your last action. Try alternative methods of performing the same action. If problems persist, contact (contact)." />
//
//  <!-- SMTP email configuration defaults -->
//  <add key="SmtpDefaultDomain" value="mydomain.com" />
//  <add key="SmtpServer" value="mail.mydomain.com" />
//  <add key="SmtpPort" value="25" />
//  <add key="SmtpAuthUser" value="" />
//  <add key="SmtpAuthPassword" value="" />
//

/// <summary>
/// Minimal class for retrieving typed values from the 
/// &lt;UnhandledException&gt; custom NameValueCollection .config section
/// </summary>
internal class Config
{
	private const string _strSectionName = "UnhandledException";
	private static NameValueCollection _nvc;

	private static void Load()
	{
		if( _nvc == null )
		{
			object o = null;
			try
			{
				o = System.Configuration.ConfigurationManager.GetSection( _strSectionName );
			}
			catch
			{
				// We are in an unhandled exception handler
			}

			if( o == null )
			{
				// we can work without any configuration at all (all defaults)
				_nvc = new NameValueCollection();
			}
			else
			{
				try
				{
					_nvc = (NameValueCollection)o;
				}
				catch( System.Exception ex )
				{
					throw new ConfigurationErrorsException( "The <" + _strSectionName + "> section is present in the .config file, but it does not appear to be a name value collection.", ex );
				}
			}
		}
	}

	/// <summary>
	/// retrieves integer value from the 
	/// &lt;UnhandledException&gt; custom NameValueCollection .config section
	/// </summary>
	public static int GetInteger( string key, int Default )
	{
		Load();
		string strTemp = _nvc[ key ];

		if( string.IsNullOrEmpty( strTemp ) )
			return Default;

		try
		{
			return Convert.ToInt32( strTemp );
		}
		catch( Exception )
		{
			return Default;
		}
	}

	/// <summary>
	/// retrieves boolean value from the 
	/// &lt;UnhandledException&gt; custom NameValueCollection .config section
	/// </summary>
	public static bool GetBoolean( string key, bool Default )
	{
		Load();
		string strTemp = _nvc[ key ];

		if( string.IsNullOrEmpty( strTemp ) )
			return Default;

		switch( strTemp.Substring( 0, 1 ).ToLower() )
		{
		case "1":
		case "t":
		case "y":
			return true;

		default:
			return false;
		}
	}

	/// <summary>
	/// retrieves string value from the 
	/// &lt;UnhandledException&gt; custom NameValueCollection .config section
	/// </summary>
	public static string GetString( string key, string Default )
	{
		Load();
		string strTemp = _nvc[ key ];

		if( string.IsNullOrEmpty( strTemp ) )
			return Default;

		return strTemp;
	}

	/// <summary>
	/// retrieves relative or absolute path string from the 
	/// &lt;UnhandledException&gt; custom NameValueCollection .config section
	/// </summary>
	public static string GetPath( string Key )
	{
		Load();
		string strPath = GetString( Key, "" );

		// users might think we're using Server.MapPath, but we're not
		// strip this because it's unnecessary (we assume website root, if path isn't rooted)
		if( strPath.StartsWith( "~/" ) )
			strPath = strPath.Replace( "~/", "" );

		if( Path.IsPathRooted( strPath ) )
			return strPath;
		else
			return Path.Combine( AppBase, strPath );
	}

	private static string AppBase
	{
		get { return Convert.ToString( System.AppDomain.CurrentDomain.GetData( "APPBASE" ) ); }
	}
}

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License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

About the Author

Andy Searls
Software Developer (Senior) Belami
United States United States
No Biography provided

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Web02 | 2.8.140721.1 | Last Updated 17 Mar 2008
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