如何在不显式调用被引用程序集的方法的情况下向其提供值？

Question

Currently I have a static class that I use as my logging module. I've added the class to my visual studio solution. Within the class I've specified the name and location of the log file to use. Which lets me do stuff like this – which I like and want.

Logger.Information(“Page_Load”,”controls loaded correctly”);

I'd like to refactor the code and move the logging functionality into a separately compiled assembly, if I did this I would then need to pass in the log file name and location to save the files too.

However I don't want to have to supply this information every time I call the 'Logging' method, this would be bad...

Logger.Informtaion(“Page_Load”,”controls loaded correctly”,”logfile.txt”,”c:\temp”);

Is there any way I can supply this information without having to specify it within each page or via the method call.

Answer 1

For sure. The simplest thing would be to add a single key to the web.config file, which your class looks at by using the ConfigurationManager.

<configuration>
<appSettings>
  <add key="logfile" value="c:\log.txt" />
</appSettings>

<system.web>
...
</system.web>
</configuration>


string logfile = ConfigurationManager.AppSettings["logfile"]

If your logging class is more complex than just one or two configuration options, consider building a ConfigurationSection class to go along with it, which would allow you to create your own section in the web.config.

The configuration approach is good for this type of thing, because then you avoid hard-coding the logfile path into your application code (such as passing it into a static initialization method), which would require a recompile if you needed to change the logging path. However, you should only need to look up the logfile path once, upon creation of your logging class.

Answer 2

1. I feel obliged to ask if you've investigated using TraceListener and the System.Diagnostics namespace with its built-in logging (as opposed to rolling your own). It's quite extensible.

2. Have you considered making your logger non-static? Perhaps a singleton? This is the classic example for an appropriate use of the Singleton pattern.

Answer 3

Sure,

Create an initialize method on your static class and pass the file into the initialize mentod. Then call the method at application start.