/// <summary>
/// Handles logging of messages for events that the application throws out
/// </summary>
/// <param name="showMessagebox">"True" will force a message box to appear regardless of application settings</param>
/// <param name="messageLevel">Integer determining error level based on above legend</param>
/// <param name="error">Exception returned from try-catch statement; may be null</param>
/// <param name="context">What the application was doing at the time of the message</param>
public static void handleMessage(bool showMessagebox, int messageLevel, Exception error, string context)
{
MessageLevelDefinition messageDef = MessageLevel.level(messageLevel);
if (messageLevel <= _eventViewerLoggingLevel)
{
logEventViewerEvent(messageDef, error, context);
}
if (messageLevel <= _applicationLogFileLoggingLevel)
{
logApplicationLogFileEntry(messageDef, error, context);
}
if (showMessagebox || _debugMode)
{
if (error != null)
{
MessageBox.Show(messageDef.messageBoxIntro + "\n\nContext:\n" + context + "\n\nError message:\n" + error.Message, messageDef.messageBoxTitle);
}
else
{
MessageBox.Show(messageDef.messageBoxIntro + "\n\nContext:\n" + context + "\n\nNo Exception object generated", messageDef.messageBoxTitle);
}
}
}
/// <summary>
/// When given an integer representation of a message level, returns the full MessageDefinition. Returns a default MessageDefinition if none is found.
/// </summary>
/// <param name="levelNumber">Integer representing message level - matches with the index in the _messageLevelDict</param>
/// <returns></returns>
public static MessageLevelDefinition level(int levelNumber)
{
if (_messageLevelDict == null)
{
buildDefaultDict();
}
if (_messageLevelDict.ContainsKey(levelNumber))
{
return(_messageLevelDict[levelNumber]);
}
else
{
MessageLevelDefinition unconfiguredErrorMessage = new MessageLevelDefinition();
unconfiguredErrorMessage.levelName = "Incorrectly Handled Error";
unconfiguredErrorMessage.messageBoxTitle = "Incorrectly Handled Error";
unconfiguredErrorMessage.messageBoxIntro = "An incorrectly handled error has occurred. Please report this to the developer, who will need to ensure that the error level number has been added to MessageLevel._messageLevelDict.";
unconfiguredErrorMessage.windowsErrorLevel = EventLogEntryType.Warning;
return(unconfiguredErrorMessage);
}
}
/// <summary>
/// Adds a new message definition to _messageLevelDict, or updates an existing one
/// </summary>
/// <param name="levelNumber">Integer code for the message level</param>
/// <param name="levelName">Short name for the message level (e.g. "Warn", "Fatal", "Info")</param>
/// <param name="messageBoxTitle">Title that will be used in any MessageBox created for this message</param>
/// <param name="messageBoxIntro">Intro text that will be used in any MessageBox created for this message</param>
/// <param name="windowsErrorLevel">Windows error level, used when creating an event in Event Viewer</param>
public static void addMessageDefinition(int levelNumber, string levelName, string messageBoxTitle, string messageBoxIntro, EventLogEntryType windowsErrorLevel)
{
if (_messageLevelDict == null)
{
buildDefaultDict();
}
MessageLevelDefinition levelDef = new MessageLevelDefinition();
levelDef.levelName = levelName;
levelDef.messageBoxTitle = messageBoxTitle;
levelDef.messageBoxIntro = messageBoxIntro;
levelDef.windowsErrorLevel = windowsErrorLevel;
if (_messageLevelDict.ContainsKey(levelNumber))
{
_messageLevelDict[levelNumber] = levelDef;
}
else
{
_messageLevelDict.Add(levelNumber, levelDef);
}
}
/// <summary>
/// Currently not functional, need an installer to create the Event Viewer source
/// Logs an event in the Windows Event Viewer, spawns a message box if this fails
/// </summary>
/// <param name="messageDef">Definition of the message type</param>
/// <param name="error">Exception, if there was one</param>
/// <param name="context">Specifies what the application was doing when the error occurred</param>
private static void logEventViewerEvent(MessageLevelDefinition messageDef, Exception error, string context)
{
string eventContent = "Logged at " + DateTime.Now + " (" + DateTime.UtcNow + ") UTC\n\n"
+ "Error Message: " + error.Message + "\n\n"
+ "Application error level: " + messageDef.levelName + "\n\n"
+ "HResult: " + error.HResult + "\n\n"
+ "Source: " + error.Source + "\n\n"
+ "TargetSite: " + error.TargetSite + "\n\n"
+ "Stack Trace:\n" + error.StackTrace;
try
{
if (!EventLog.SourceExists(error.Source))
{
EventLog.CreateEventSource(error.Source, "Application");
}
EventLog.WriteEntry(error.Source, eventContent, messageDef.windowsErrorLevel);
}
catch (Exception e)
{
MessageBox.Show("Unable to log event viewer message: " + e.Message + "\n\n" + eventContent);
}
}
/// <summary>
/// Saves events to the application log file, creating the file if it doesn't exist
/// </summary>
/// <param name="messageDef">Definition of the message type</param>
/// <param name="error">Exception, if there was one</param>
/// <param name="context">Specifies what the application was doing when the error occurred</param>
private static void logApplicationLogFileEntry(MessageLevelDefinition messageDef, Exception error, string context)
{
// Confirm the log file location has been specified
if (_applicationLogFileLocation == null)
{
return;
}
// Create the log file, if it doesn't exist
if (!File.Exists(_applicationLogFileLocation))
{
try
{
FileInfo logFileInfo = new FileInfo(_applicationLogFileLocation);
Directory.CreateDirectory(logFileInfo.Directory.FullName);
XmlDocument newDoc = new XmlDocument();
newDoc.LoadXml("<logs></logs>");
XmlTextWriter xmlWriter = new XmlTextWriter(_applicationLogFileLocation, null);
xmlWriter.Formatting = Formatting.Indented;
newDoc.Save(xmlWriter);
xmlWriter.Dispose();
}
catch (Exception e)
{
MessageBox.Show("Unable to create log file in " + _applicationLogFileLocation + "\n\n"
+ e.Message);
}
}
// Load the Xml document
XmlDocument logFile = new XmlDocument();
logFile.Load(_applicationLogFileLocation);
XmlNode rootNode = logFile.SelectSingleNode("logs");
// Build the log entry
XmlNode newNode = logFile.CreateElement("log");
XmlAttribute utcTimeAttribute = logFile.CreateAttribute("utctime");
utcTimeAttribute.Value = DateTime.UtcNow.ToString();
newNode.Attributes.Append(utcTimeAttribute);
XmlAttribute levelAttribute = logFile.CreateAttribute("level");
levelAttribute.Value = messageDef.levelName;
newNode.Attributes.Append(levelAttribute);
XmlAttribute contextAttribute = logFile.CreateAttribute("context");
contextAttribute.Value = context;
newNode.Attributes.Append(contextAttribute);
if (error != null)
{
newNode.InnerText = error.Message;
}
else
{
newNode.InnerText = "No Exception object for event";
}
// Append the log entry
rootNode.AppendChild(newNode);
// Save the log file
logFile.Save(_applicationLogFileLocation);
}
