ASP/ASP.NET: Tricks and Tips How to get Microsoft’s Programming Language to work for you By Wade Tripp Park University

Disclaimer I am not an expert in all the details, just giving a general overview of how it works, and there are over a dozen ways how to do things, with half of them working.

Who are YOU?

History of ASP (abbreviated) VBScript –Client Side –Possible for all sorts of problems, intentional or not –Required the client to have IE installed

History of ASP (abbreviated) ASP –Server Side Scripting –Browser independent –Required special server software but….. –Very much interpreted and scripting –Created many bad programming habits

History of ASP (abbreviated) ASP.NET –Server Side Scripting –Able to program in many languages –Permits good programming practice but…. –Steep learning curve

How ASP works Browser requests a web page Web server gets request and loads file from hard drive Web server sends the file to asp.dll to process Returns to the browser the processed page

How ASP.NET works (interpreted) Browser requests a web page Web server gets request and loads the file from hard drive Web server sends the file to aspnet_isapi.dll to process Returns to the browser the processed page

How ASP.NET works (compiled) Browser requests a web page Web server gets request and loads dll from hard drive Web server sends the file to aspnet_isapi.dll to process Returns to the browser the processed page The code does not have to be on the server

Differences between ASP ASP Quick and easy to use and do Easy to modify and tweak Uses the very basics and forgiving ASP.NET (Interpreted) Increased flexibility No need to code everything from scratch Memory of events Still can get confusing for large projects ASP.NET (Compiled) Most flexible Hardest to understand Easy to get good programming standards

Differences between ASP Simple and quick – ASP Ex – Date modified, Alert Message Repeated on several pages – ASP.NET Interpreted Ex – Announcement on several web pages Advanced Application – ASP.NET Compiled Ex – Registration form

Getting down to code ASP/ASP.NET handles the appearance, input/output of a web page The Code Behind focuses on the thinking and language “Code Behind” can happen in a web page itself and does not have to be in a.vb or.cs file Any language can use in theory, VB and C# are the ones Microsoft has preconnected in Visual Studio, but almost any can be used. Java is not used for various legal reasons.

Simple Displaying Stuff To simply display stuff ( traditionally used in ASP ) you use ASP is forgiving, so if you miss the ( ) in Response.Write, it has variant type and other items. But if you save it as.aspx it may not work.

Is.asp the same as.aspx No, but they are so close that most of the time you can just do minor changes and tweaks going from asp to aspx. Several things are required (Declaration of variables) The big change with CDONTS. The method for sending out mail was changed from ASP to ASP.NET IIS 5 to IIS 6 for various reasons [Security being the main one]

QueryString vs. Forms There are two ways to get information. QueryString/Get –Information is sent via the URL Form/Post –Information sent in the page

QueryString It appears in the URL.. /index.asp?Sample=test&B1=Submit The ? Marks the end of the URL and the rest are variables Items are recoded for valid characters (make spaces into +, & turned into %26 and other items) Advantage jump directly to section, performing items

QueryString Disadvantages Easily find the information via History and guessable test.asp?ID=45 Limited on how much information can be passed. Dependant on browser of 1000, characters

Form What is normally used with web pages Better to make things go better and organized, less chance of being reviewed

Actually using it <% Dim intNumber as integer intNumber = Request.QueryString(“Test”) intNumber = Request.Form(“Test”) Response.Write (intNumber) %>

TIP - Polish Notation Based on ideas of Jan Lukasiewicz Standard documenting is putting type in front of name intName – Integer strName – String bolName – Boolean values

TIP - Polish Notation Also good for ASP txtName – Textbox lblName – Label panName – Panel lstName – List …. It keeps you organized

Basics of ASP.Net When it is transformed by the compiler it becomes What all happened? ASP.NET is transformed into HTML

How does information get stored Information is stored in a hidden view, called the Viewstate It sends and organizes the information for each variable and items The information is stored for all server objects

TIP – Don’t make everything label Each ASP.NET item requires resources Don’t use labels for standard items. Why? Because it takes extra resources and time to download

TIP – Don’t make everything label Each ASP.NET item requires resources Don’t use labels for standard items. Why? Because it takes extra resources and time to download

TRICKS – Storing information Information can be handled Session Application Variable Value of ASP Object Hidden Field Passed Variable in Form

TRICKS – Database Reading Can connect to database via connection with SQL, Access, Informix, etc… anything that permits ODBC Warning – Access can cause problems with older web servers

TRICKS – AutoPostback Permits scripting to run after an item has been altered Requires Javascript

TRICKS – Validation Lets a user check to make sure a field is probably filled out Normally uses Javascript to validate There are a few ways around it (disable Javascript)

TRICKS – Smart Navigation Permits forms not to blink by using ‘IFRAME’

TRICKS – ME - ASP Used to find what variables and objects are used Remove the Me. after you go though the form