Migration from ASP to ASP.NET

Migration from ASP to ASP.NET Anand M. Hegde Developer Support Engineer Microsoft Developer Support Microsoft Corporation

Overview Why should you migrate? Introduction to Microsoft® ASP.NET Key changes from ASP to ASP.NET Migrating from ASP to ASP.NET Migrating applications that use COM components Migrating applications that use databases Migration best practices ASP to ASP.NET compatibility FAQ Resources for ASP.NET and migration

Why Should You Migrate? Increased scalability and reliability Minimum 2X to 3X performance gain Built-in cross-browser compatibility Rich server-side controls, Microsoft Visual Studio® .NET designer support, and configuration options X-copy deployment of pages and components Better debugger; tracing options Content-code separation Take advantage of new caching features Enhanced state-management features ASP and ASP.NET can run side-by-side if required Many new features

Before You Migrate Get a good understanding of ASP.NET Know the changes from ASP to ASP.NET Understand that migration requires code changes Although ASP.NET has excellent backward compatibility, migration may not be as easy as it seems in many cases

Introduction to ASP.NET ASP.NET is: A new programming framework for Web applications An overhaul of ASP A part of Microsoft .NET Compiled and event driven programming model It permits you to: Rapidly develop powerful Web applications and services Easily build, deploy, and run Web applications that can target any browser or device It requires: Microsoft Windows® 2000 or later for hosting and development

ASP.NET Request Flow ASPX engine Gen’d page class file Page class ASPX file Request Parse Generate Instantiate, process, and render Response Request Code behind class file Response Instantiate

ASP.NET Page Life Cycle ASP.NET pages are event based Event flow in ASPX pages Page_Init: the page and controls are initialized Page_Load: all the controls and page are loaded Change events for controls are processed Click events for controls are processed Page_PreRender: page is about to render Page_Unload: page is unloaded from memory

ASP Programming Models Two types of programming models exist ASPX page only: contains HTML, control tags, and code Code behind model: ASPX file contains HTML and control tags, and a “code behind” file contains code A true separation between code and content One File Two files. (“code behind” model) Page.aspx Page.aspx Page.aspx.vb <Tags> + Code <Tags> Code

ASP.NET Features Life made easy for developers Excellent backward compatibility with classic ASP Visual Studio designer support, rich server controls, and base class library support Write code in the language of your choice Call Microsoft Win32® APIs directly Structured error handling Great debugging and tracing support

ASP.NET Features (2) Performance, scalability, and reliability Compiled code means speed Cache APIs to improve performance and scalability Built-in support for WebFarms and WebGardens Nonstop availability and protection against deadlocks, memory leaks, and so on

ASP.NET Features (3) Easy deployment X-copy deployment Dynamic updates without interrupting the service No more registry! — u se XML-based configuration files New application models Develop mobile Internet applications with ease Built-in support to use XML WebServices More control with the new security model Flexible session state management Many other new features

Core Object Changes Request object changes: Request(item) , Request.QueryString(item) , and Request.Form(item) now return a name value collection In classic ASP, they return an array of strings Use Response.Write with caution It will output results at the top of the page before the <HTML> tag Instead: Use server controls (placeholder) Use <% %> tags if you want the output to appear in the right place Each of the core objects now have many new properties and methods. There are some new objects available For example: cache, user and trace

Structural Changes One page – one language No mixing of languages in single page A page can have only one server-side Form tag and it must submit to the same page An ASPX page may contain: Directives: <%@ Directive %> Server controls: <tag runat=server> Code blocks: <script runat=server> Data binding expressions: <%# %> Server-side comments: <%-- --%> Server-side includes:  Render code: <%= %> and <% %>

Structural Changes (2) Code block – related changes You cannot declare functions inside <% %> tags Declare all your functions and variables inside the server-side <SCRIPT> blocks <Script runat=“server” language=“vb”> dim gVar as String ‘Page level variable private sub MySubRoutine() Label1.Text = gVar End Sub </Script >

Structural Changes (3) No Render functions permited Change: <% MyRenderFunction Sub MyRenderFunction() %> <h1> Hi there! </h1> <%end sub%> To: <% Call MyRenderFunction()%> <script runat=“server” language=“vb”> Response.Write(“Hi there!”) </script>

Structural Changes (4) New page directives In ASP, directives had to be at the top of the page, but you do not have to do this anymore You can now have multiple directives on the same page Sample page directive: <%@ Page Language="VB" ContentType="text/xml" %> See the documents on new page directives

Application Configuration Changes ASP.NET application settings are stored in XML configuration files Types of configuration files Machine.config Contains machine-wide settings Web.Config Contains project/application-wide settings Easy programmatic access to the data in these files Some of the settings in the IIS snap-in are ignored For example: application protection level, session state

Session Management Changes New session state storage mechanisms InProc – session data stored on local computer (fastest) StateServer – session data stored in a state service that can be located anywhere; ideal for WebFarms (faster) SQLServer – session data stored in Microsoft SQL Server™ (fast) Off – disable session state Session state can be configured using <sessionState> section Can store COM components in session only in InProc Can store managed components in any session state modes

Security Related Changes The IIS part of the security remains same New robust and flexible security model is based on the security sections in the configuration files New authentication modes Windows: uses Windows Authentication Forms: uses cookie-based custom logon forms Passport: uses the Microsoft .NET Passport Service None: no authentication Authorization modes permit you to control access to resources: File authorization URL authorization Permit and deny users access to the application

Migrating VBScript to Visual Basic .NET No VBScript in ASP.NET — it’s all Microsoft Visual Basic® .NET! Changing the file name extension to .aspx is the first step Visual Basic language changes Option Explicit is now the default No more “variant” type — use type “Object” Method and function calls with parameters now require parenthesis, so change: <% Response.Write “Hi” %> to <% Response.Write (“Hi”) %> By default, arguments are passed by value Arrays are now zero based

Visual Basic Language Changes Let and Set are not supported, so change: Set MyObj1 = MyObj2 to MyObj1 = MyObj2 No more default properties (except for indexed properties), so change: MyString as string = Textbox1 to MyString as string = Textbox.Text Integer data type is now 32 bits and a Long data type is 64 bits Use structured error handling (try catch block) instead of On Error (On Error still works) Must cast data types explicitly: Response.Write (“Count=“ & CStr(MyCount)) or Response.Write(“Count=“ & CType(MyCount, String))

Visual Basic Language Changes (2) Must have spaces around “&” while doing string concatenation, so change: x = str1&str2 to x = str1 & str2 Property Get, Property Set, and Property Let are not supported anymore, so instead use: Public Property MyCount as Integer Get MyCount = InternalValue End Get Set InternalValue = value End Set End Property

Migrating JScript to JScript .NET Start by changing the file name extension to .aspx Declare your variables explicitly Microsoft JScript® .NET language changes You can now pass variables by reference “ expando” modifier available to extend user-defined objects Can use COM components directly from JScript .NET Server Object’s methods are case sensitive The Arguments object is not available — use a parameter array instead Functions cannot be redefined For Large pages, move function/method code out of <% %> blocks to <Script runat=“server”> blocks

Migrating Applications that Use COM Components COM related changes: ASP.NET uses MTA instead of STA Pages with STA components may or may not perform well Early binding is preferred in ASP.NET Cannot use ASPCOMPAT with WebServices COM Interop Can use all your former COM components in ASP.NET Use ASPCOMPAT keyword if you plan to use existing STA components in ASP.NET Use ASPCOMPAT only when using STA objects or when your COM objects access ASP intrinsic objects

COM Objects Migration — FAQ What if the page contains both MTA and STA? Use ASPCOMPAT What if I have a middle tier containing COM objects? Use horizontal or vertical migration strategies What about the performance if I use existing COM objects? Very little overhead if the method does substantial tasks Significant overhead if the method does not do much

COM Objects Migration — FAQ (2) What about deploying COM objects used in ASPX pages? If you want to use Server.CreateObject, then there is no change If you use early binding then use the PIA (Primary Interop Assembly) for the COM component and make sure you deploy the PIA on the target server How can I use STA components from XML WebServices? Register the component in COM+ and make sure you are running Windows 2000 SP2

Migrating Applications that Use Databases Data access changes ADO (through Interop) can be used, but Microsoft does not recommend it ADO and ADO.NET are quite different ADO.NET is not exactly backward compatible Three main objects in ADO.NET: DataSet, DataReader, and DataAdapter Two built-in managed data providers: SQLClient and OLEDB Built-in designer support for ADO.NET objects in Visual Studio .NET

Migrating Applications that Use Databases (2) Strategies Rewrite ADO code in ADO.NET instead of migrating Keep ADO code as a short term approach If you use ADO code in ASP pages, use Primary Interop Assembly for ADO on both the developer box and the server If you need read-only data, use a DataReader

Data Access Migration — FAQ What if my application has straight ADO code in ASP pages? Use ASPCOMPAT to use the code as it is (may be slower) Rewrite the data access code to use ADO.NET What if my application has COM objects that use data access? Use the ASPCOMPAT attribute (if component uses STA) What if my database has no managed providers? You can use OLEDB providers in ADO.NET If there are no OLEDB providers, use ODBC managed provider

Data Access migration — FAQ (2) What if I have a data access tier? Make these objects call Web Services or managed components Later on, modify the presentation layer to use only .NET middle tier Do I have to package ADO Components during deployment? Make sure your server has MDAC 2.6 installed Make sure you also deploy the PIA for ADODB on the server

General Migration Strategy Identify the parts of the application that you have to migrate Plan very carefully and try to have minimal impact on the existing application during the migration In a multi-tier scenario, take the horizontal or vertical approach Horizontal – migrate the whole tier (middle/presentation) at the same time Vertical – migrate some pages, some components, at the same time Decide if you want to reuse existing COM components

General Migration Strategy (2) Decide if you want to keep current ADO code for a while Rename the file name extension from .asp to .aspx Make the language-specific changes first Make COM- and database-specific changes Test, test, test

Migration Best Practices General If the application is relatively small, consider rewriting If the application is very large, then plan carefully and migrate part by part If you only want to make a syntactic port, then consider only ASPX pages (that is, not using the “code behind” model) and do not make unnecessary changes You do not have to port the whole site at the same time Consider migrating the slow/critical parts Remember, you can run ASP and ASP.NET side-by-side Try to migrate the read-only pages first Write automated tools to do some tasks

Migration Best Practices (2) Language related Strongly type all the variables If possible, convert all the On Error statements to try catch blocks Remember that they may not be as easy as they look Convert Include files into assemblies or user controls (.ascx) Use call keyword for function calls and use parenthesis for function and subroutine calls Identify default properties and replace them appropriately Always use Option Explicit

Migration Best Practices (3) Data access related If you have a data access tier, move it into .NET COM related Always use early binding Explicitly free resources from code Project management related Keep two code trees while migrating, and make sure to update both of them while adding changes to the existing Web site First try to modify the existing code as it is After you complete this, try to modify the application to use the advantages provided by .NET

Migration Best Practices (4) Testing related Update existing links to your Web site/pages because the file name extension is now .aspx Use a link checker to check any broken links, images, paths, and so on Test very well

ASP to ASP.NET Compatibility — FAQ How can ASP and ASP.NET co-exist? Because they have different file name extensions (.asp and .aspx) Because they have different application settings (registry and config files) Can they share session and application data? No – w rite custom code or use third-party component What about Global.asa in ASP.NET? In ASP.NET, it is called as Global.asax

ASP to ASP.NET Compatibility — FAQ (2) Can I use .NET components from ASP, and COM components from ASP.NET? Yes – use CCW to call managed components from ASP Yes – u se RCW to call COM components from ASP.NET What about the anonymous account in ASP.NET? Remains the same What about the hosting process in ASP.NET? ASP.NET applications run under ASPNET_WP.EXE By default, ASP.NET worker process runs under an account called ASPNET

ASP to ASP.NET Compatibility — FAQ (3) Do I need to write code for different browsers? No – ASP.NET produces HTML 3.2 compliant output Can I still use ADO from ASP.NET? Yes – y ou can use ADO through Interop, but ADO.NET is preferred What about Include files? Can be used, but better to convert them to class libraries or user controls (.ascx) instead Can I call ASP pages from ASPX and vice versa? Yes

ASP.NET Resources ASP.NET Quick Start Tutorials Authentication in ASP.NET Security ASP.NET Security Session State in ASP.NET ASP.NET Configuration http://www.gotdotnet.com http://www.asp.net http://www.ibuyspy.com

Migration Resources Migrating to ASP.NET: Key Considerations Migrating ASP Pages to ASP.NET Converting ASP to ASP.NET Upgrading to Microsoft .NET on GotDotNet Upgrading to .NET on MSDN Upgrading from JScript to JScript .NET Microsoft .NET/COM Migration and Interoperability Q314775 , “INFO: Migrating Visual InterDev Design-Time Controls to ASP.NET” .NET Migration Case Study

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Migration from ASP to ASP.NET

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Migration from ASP to ASP.NET