asp.net Error pocessing method

Asp.net|error errors are grouped into four categories: configuration errors, parse errors, compilation errors, and Run-time errors.
By default, the information displayed for Run-time errors is the call stack (the chain of procedure calls that cause the exception). If debug mode is enabled, ASP.net displays the line number in the source code where a run-time error occurred.
asp.net enables you to specify whether to display an error to a local client, a remote client, or both. By default, errors are displayed only to local clients (that is, clients on the same computer on which the server resides). You can also specify a custom error page to redirect the client to the page in the event of an error.
In addition to redirecting all errors to a common page, you can assign specific error pages to specific error status codes. The <customerrors> configuration section supports the internal <error> tag, which associates the HTTP status code with the custom error page.
You can handle code errors at the page level or at the application level. The page base class exposes a HandleError method that can be overridden in a page. This method is called whenever the runtime throws an exception that is not caught.
System.Web.Mail namespaces expose classes that programmatically send e-mail messages. This is useful for notifying administrators when an error occurs.
In addition to processing errors at the page level, you can use the Application_Error event in Global.asax to handle application-level errors. This event is raised for any unhandled exception that is raised in the application.
The System.Diagnostics namespace provides a class to write to the Windows event log.