OOP Class8
Contents
Motorvehicle Diagram
http://iam.colum.edu/oop/browser/browser.aspx?f=/classsource/class7/Motor
Anatomy of an aspx page
Page Directive The page directive must be on the first line of an aspx page. It consists of Name/Value Pairs and sets parameters that will be used throughout the execution of the page ie. the language.
<%@ Page language="c#" debug="True" trace="False"%>
C# Code may be embedded in the page using script tags similar to javascript
<script language="c#" runat="server">
</script>
Notice the runat attribute is set to 'server'. This is what makes the code execute on the server rather than be parsed by the client.
Console applications start executing in the main method
<csharp>public static void Main() {}</csharp>
The .Net Framework can also execute on the web. Rather than having a Main method a web page starts it's execution with a method called Page_Load
<csharp>public Page_Load { }</csharp>
There are actually several method that are executed in an aspx page.
http://samples.gotdotnet.com/quickstart/aspplus/
Simple Aspx Page
http://iam.colum.edu/oop/classsource/class8/Aspx/hello.aspx hello.aspx
http://iam.colum.edu/oop/classsource/class8/Aspx/hello2.aspx hello2.aspx
http://iam.colum.edu/oop/classsource/class8/Aspx/Label.aspx Label.aspx
In class Build three hello aspx pages similar to the ones above
Dogs on the web
HTML Forms
Http is a stateless protocol. There is mo mechanism built in to the protocol that allows the server to remeber clients or requests. An http simply responds to http verbs GET, POST, PUT, DEL, TRACE etc. contained in RFC 2068 HTTP/1.1
Old html forms post information using forms in 2 ways with a get or a post http request.
Get
- Get send information to the server using the URI. Limited to 1024 character in some browsers and servers.
Example http://iam.colum.edu/oop/classsource/class9/simpleGet.html simpleGet.html - source
The simpleGet.html pages form has the action of 'simpleGet.aspx' this mean that when the form is submitted the browser will request the 'simpleGet.aspx' with whatever parameters are in the form. Since the method = get these pararmeters will show up are query string parameters
URI and querystring parameters
URI - Universal Resource Identifier http://src.doc.ic.ac.uk/computing/internet/rfc/rfc1630.txt RFC1630
Http URI
Protcol | Host | Port | Path | File | Fragment identifier | Querystring |
---|---|---|---|---|---|---|
http:// | info.cern.ch | :8000 | /imaginary/test/ | file.html | #link | ?test=yes |