لطفا منتظر باشید ...
Publisher14.1 Comments/Troubleshooting
Many HttpContext class properties are topics in
their own right. For instance, the Application, Response, Request,
and Session properties are accessible here, but covered in detail
elsewhere in this book. A couple of methods within HttpContext,
however, might require further explanation.GetConfig sounds like it might be a way to get the
appSettings configuration information mentioned in
the previous chapter. While it is possible to use
GetConfig("appSettings") for that
purpose, it requires some casting. GetConfig returns an instance of
System.Configuration.ReadOnlyNameValueCollection, which is a private
class. To actually use the returned value, you need to cast it to a
System.Collections.Specialized.NameValueCollection. Instead of doing
this, using ConfigurationSettings.AppSettings is safer and easier.
Why is GetConfig there, then? In addition to the
appSettings section, a developer can place custom
sections within the configuration files, which is what GetConfig is
designed for.The other somewhat unusual (although much more useful) method in
HttpContext is RewritePath. The MSDN documentation on this method is,
shall we say, sparse. The real use for this method is to silently
redirect the user to a different URL.In this chapter, as in others in the book, we'll use
the following code listing as the basis for most examples in the
chapter. Unless otherwise noted, each example will consist of the
Page_Load event handler for just that particular example. Any output
messages or return values displayed will be shown as the Text
property of the ASP.NET Label control named Message or displayed by
calling Response.Write.
<%@ Page Language="vb" %>
<html>
<head>
<script runat="server">
Sub Page_Load( )
'Example code will go here
End Sub
</script>
</head>
<body>
<asp:label id="Message" runat="server"/>
</body>
</html>
Some examples will show Application handlers within
global.asax rather than the Page_Load method of
a page.
