Script

1
Script - the .NET response to Google Web Toolkit

• Gojko Adzic
• http//gojko.net
• gojko_at_gojko.com

2
Why should you care?

• A much more productive way to write and maintain
  complex JavaScript code
• Compile-time consistency check
• Refactoring support
• Full Intellisense for DOM and your own JS classes
• Lots of other VS IDE benefits
• Free (not opensource, though)

3
What Script is not

• It does not hide browser complexity
• It does not abstract away JS peculiarities
• It is not a general-purpose .NET to browser
  converter
• It is not a widget/effect library (it has some,
  but not nearly like GWT)

4
Under the hood

• Compiles C into JS directly
• Replacement for System namespace, a mashup of
  .NET and JS
• Sscorlib.dll in C for Intellisense,
• sscorlib.js in the browser
• sscompat.js provides cross-browser compatibility
• System.DHTML.Document, System.Script
  System.DHTML.Window link to the environment

5
A very simple example

• Script library project
• Compile C into javascript
• Execute from HTML
• namespace.class used to instantiate objects
• If you do the web site by hand, dont forget
  sscompat.js!

6
Visual Studio Integration

• Project templates for class libraries and web
  sites
• C editor for scriptlets (has some bugs, though)

7
MSBuild Integration

• ScriptSharp target does the job for you ltImport
  Project"(ProgramFiles)\nStuff\ScriptSharp\v1.0\n
  Stuff.ScriptSharp.targets" /gt
• Remember ltNoStdLibgtTruelt/NoStdLibgt
• Automatically added by the VS ScriptSharp template

8
Scriptlets

• Script webforms components
• Add Script assembly and page control to
  web.config
• Use main() as an entry point to the component
• No need to worry about script initialisation
• Put all scripts into App_Scripts folder (or use a
  VS template to create the project)

9
AJAX support

• Add ltscript type"text/javascript"
  src"App_Scripts/ssfx.Core.Debug.js" gt
• lt/scriptgt
• Use ScriptFX.Net.HTTPRequest for cross-browser
  compatible AJAX requests
• Supports Script transport for Cross-Domain Ajax!

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Ajax/JSON

• private void OnOKButtonClick(object sender,
  EventArgs e)
• Dictionary parameters new Dictionary()
• parameters"prefix" _prefixTextBox.Text
  
• parameters"count" 5
• _request HTTPRequest.CreateRequest("Comp
  letionList.ashx/GetItemsViaPost", HTTPVerb.POST)
• _request.SetContentAsJSON(parameters)
• _request.Invoke(new HTTPRequestCompletedCa
  llback(OnRequestComplete), null)
• private void OnRequestComplete(HTTPRequest
  request, object context)
• if (_request request)
• string values (string)_request.R
  esponse.GetObject()
• _valuesLabel.Text values.Join(",
  ")

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Behaviours

• Declaratively attach functionality to DOM
  elements
• Taken from ASP.NET Ajax (Atlas)
• Popups, watermark, autocomplete, overlay etc
• Not a lot of widgets, but you can use ExtJS with
  ExtSharp!

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More advanced options

• FxCop code analysis
• Unit testing should follow soon
• ASP.NET Ajax instead of sscorelib
• Some silverlight support
• MSN Messenger APIs
• Facebook client API
• Sidebar Gadgets

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Quirks Namespace references

• Does not work
• DOMElement runner System.DHTML.Document.GetElemen
  tById(
• runnerElementId)
• Works
• Using System.DHTML
• DOMElement runner Document.GetElementById(runner
  ElementId)

14
Quirks Compilation issues

• VS New class wizard adds System, System.Data and
  System.Xml references
• Script compilation breaks as a result
• Does not resolve indirect module dependencies
• Nested namespaces not supported

15
Quirks 0 and null comparisons

• if (something null) and if (something 0)
  compiled into if (!something)
• Try this
• Number a null
• if (a 0)
• Script.Alert("I shouldn't be seeing this???")
• Number b 0
• if (b null)
• Script.Alert("I shouldn't be seeing this
  either???")

16
Quirks Scriptlets

• Scriptlet tag has to be inside a form tag
• If not, nothing happens, but you dont get an
  alert
• Inline Scriptlets use ScriptletArguments,
  pre-compiled ones use Dictionary

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Quirks Events

• DOMEventHandler expects void() delegate
• Use Window.Event.ReturnValue to return false from
  an event

18
Whats good?

• Working with complex JS files is much very
  productive
• VS integration
• MSBuild integration
• Basic Documentation is great

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Whats not so good?

• Some unintuitive mismatch between C and JS
  type conversions, 0 and null
• Advanced stuff not documented that well
• See the samples zip in the distribution!
• Still not opensource

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Where next?

• http//gojko.net
• http//projects.nikhilk.net/ScriptSharp/
• http//code.google.com/p/extsharp/
• http//www.codeplex.com/JQuerySharp

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What next?

• Dependency Injection with Castle Oct 23rd
• Asynchronous Enterprise Applications with
  NServiceBus Nov 27th
• TDD with .NET Dec 17th
• ALT.NET Community evening Jan 13th