public class FileAppender : TextWriterAppender

Public Class FileAppender
	Inherits TextWriterAppender

public ref class FileAppender : public TextWriterAppender

type FileAppender =  
    class
        inherit TextWriterAppender
    end

The FileAppender type exposes the following members.

	Name	Description
	FileAppender	Default constructor
	FileAppender(ILayout, String)	Obsolete. Construct a new appender using the layout and file specified. The file will be appended to.
	FileAppender(ILayout, String, Boolean)	Obsolete. Construct a new appender using the layout, file and append mode.

	Name	Description
	AppendToFile	Gets or sets a flag that indicates whether the file should be appended to or overwritten.
	Encoding	Gets or sets Encoding used to write to the file.
	ErrorHandler	Gets or set the IErrorHandler and the underlying QuietTextWriter, if any, for this appender. (Inherited from TextWriterAppender.)
	File	Gets or sets the path to the file that logging will be written to.
	FilterHead	The filter chain. (Inherited from AppenderSkeleton.)
	ImmediateFlush	Gets or set whether the appender will flush at the end of each append operation. (Inherited from TextWriterAppender.)
	Layout	Gets or sets the ILayout for this appender. (Inherited from AppenderSkeleton.)
	LockingModel	Gets or sets the LockingModel used to handle locking of the file.
	Name	Gets or sets the name of this appender. (Inherited from AppenderSkeleton.)
	QuietWriter	Gets or sets the QuietTextWriter where logging events will be written to. (Inherited from TextWriterAppender.)
	RequiresLayout	This appender requires a log4net.Layout to be set. (Inherited from TextWriterAppender.)
	SecurityContext	Gets or sets the SecurityContext used to write to the file.
	Threshold	Gets or sets the threshold Level of this appender. (Inherited from AppenderSkeleton.)
	Writer	Sets the TextWriter where the log output will go. (Inherited from TextWriterAppender.)

	Name	Description
	ActivateOptions	Activate the options on the file appender. (Overrides AppenderSkeletonActivateOptions.)
	AddFilter	Adds a filter to the end of the filter chain. (Inherited from AppenderSkeleton.)
	Append(LoggingEvent)	This method is called by the DoAppend(LoggingEvent) method. (Overrides TextWriterAppenderAppend(LoggingEvent).)
	Append(LoggingEvent)	This method is called by the DoAppend(LoggingEvent) method. (Overrides TextWriterAppenderAppend(LoggingEvent).)
	ClearFilters	Clears the filter list for this appender. (Inherited from AppenderSkeleton.)
	Close	Closes the appender and release resources. (Inherited from AppenderSkeleton.)
	CloseFile	Closes the previously opened file.
	CloseWriter	Closes the underlying TextWriter. (Overrides TextWriterAppenderCloseWriter.)
	ConvertToFullPath	Convert a path into a fully qualified path.
	DoAppend(LoggingEvent)	Performs threshold checks and invokes filters before delegating actual logging to the subclasses specific [M:Append(LoggingEvent)] method. (Inherited from AppenderSkeleton.)
	DoAppend(LoggingEvent)	Performs threshold checks and invokes filters before delegating actual logging to the subclasses specific [M:Append(LoggingEvent[])] method. (Inherited from AppenderSkeleton.)
	Equals	Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
	FilterEvent	Test if the logging event should we output by this appender (Inherited from AppenderSkeleton.)
	Finalize	Finalizes this appender by calling the implementation's Close method. (Inherited from AppenderSkeleton.)
	Flush	Flushes any buffered log data. (Inherited from TextWriterAppender.)
	GetHashCode	Serves as a hash function for a particular type. (Inherited from Object.)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	IsAsSevereAsThreshold	Checks if the message level is below this appender's threshold. (Inherited from AppenderSkeleton.)
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	OnClose	Close this appender instance. The underlying stream or writer is also closed. (Overrides TextWriterAppenderOnClose.)
	OpenFile	Sets and opens the file where the log output will go. The specified file must be writable.
	PreAppendCheck	This method determines if there is a sense in attempting to append. (Inherited from TextWriterAppender.)
	PrepareWriter	Called to initialize the file writer (Overrides TextWriterAppenderPrepareWriter.)
	RenderLoggingEvent(LoggingEvent)	Renders the LoggingEvent to a string. (Inherited from AppenderSkeleton.)
	RenderLoggingEvent(TextWriter, LoggingEvent)	Renders the LoggingEvent to a string. (Inherited from AppenderSkeleton.)
	Reset	Closes any previously opened file and calls the parent's Reset. (Overrides TextWriterAppenderReset.)
	SafeOpenFile	Sets and opens the file where the log output will go. The specified file must be writable.
	SetQWForFiles(Stream)	Sets the quiet writer used for file output
	SetQWForFiles(TextWriter)	Sets the quiet writer being used.
	ToString	Returns a String that represents the current Object. (Inherited from Object.)
	WriteFooter	Writes a footer as produced by the embedded layout's Footer property. (Overrides TextWriterAppenderWriteFooter.)
	WriteFooterAndCloseWriter	Writes the footer and closes the underlying TextWriter. (Inherited from TextWriterAppender.)
	WriteHeader	Writes a header produced by the embedded layout's Header property. (Overrides TextWriterAppenderWriteHeader.)

Logging events are sent to the file specified by the File property.

The file can be opened in either append or overwrite mode by specifying the AppendToFile property. If the file path is relative it is taken as relative from the application base directory. The file encoding can be specified by setting the Encoding property.

The layout's Header and Footer values will be written each time the file is opened and closed respectively. If the AppendToFile property is then the file may contain multiple copies of the header and footer.

This appender will first try to open the file for writing when ActivateOptions is called. This will typically be during configuration. If the file cannot be opened for writing the appender will attempt to open the file again each time a message is logged to the appender. If the file cannot be opened for writing when a message is logged then the message will be discarded by this appender.

The FileAppender supports pluggable file locking models via the LockingModel property. The default behavior, implemented by FileAppenderExclusiveLock is to obtain an exclusive write lock on the file until this appender is closed. The alternative models only hold a write lock while the appender is writing a logging event (FileAppenderMinimalLock) or synchronize by using a named system wide Mutex (FileAppenderInterProcessLock).

All locking strategies have issues and you should seriously consider using a different strategy that avoids having multiple processes logging to the same file.

Reference