Listeners : 7

From a component will also be written to the ASP.net trace okay logo confusing but it's just capturing messages that are going to ASP.net trace what it does is it let you integrate ASP.net tracing techniques with the system.diagnostics tracing techniques tried all the trace messages to a single tracing output is a consolidated view of everything that is going on within your application you can use it to do things like track the flow of execution for an application display data critical points throughout it web.

 Forms life cycle and you can discover how web forms interact with various other components in your application to think a look at how you can put this trace listener to work to direct trace messages from a component to an ASP.net webpage you need to configure the webpage trace listener in the web.config file type this trace element within the system.diagnostics that creates a listener called web listener that's a name that I choose and it references that webpage trace listener to this makes that listener available for this application is external component that will provide trace information it uses the system.diagnostics namespace and it just defines a very simple customer class in which all of the action takes place within the constructor the constructor receives.

A custom name string we check to see whether or not the length of that string is equal to zero if it is then we write out a message using the system.diagnostics.trace right line method indicated his blank and we specify where this message is coming from whether or not the names blank we also write out another message saying that the customers create a very simple example but the idea here is that because this customer object is within the app code folder it's a separate component that can send messages to ASP.net.

Typically if we included code like this it would just output it to the components trace listeners this is the kind of code that could appear in any.net component including ones that aren't necessarily intended for use with an ASP.net application what's different here is that the webpage trace listener what you receive the trace output from such components within your ASP.net applications and integrated together with the ASP.net trace messages the messages that are generated from the webpage itself now to enable tracing and components that use the system.diagnostics tracing you can use a compiler switch when you compile the application or you can make an entry in the config file for the component to turn that switch on automatically.

When the codes compiled so go back over the web.config file and scroll down here and notice that I have this compiler's element with a couple of compiler elements as child elements and all contained within the system.co.element the idea here is that because the code for this component the customer component is in the app code folder is automatically compiled when ASP.net application is compiled and a reference is automatically added to the web application.