Script# - the.NET response to Google Web Toolkit Gojko Adzic

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)

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)

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

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, don’t forget sscompat.js!

Visual Studio Integration Project templates for class libraries and web sites C# editor for scriptlets (has some bugs, though)

MSBuild Integration ScriptSharp target does the job for you Remember True Automatically added by the VS ScriptSharp template

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)

AJAX support Add Use ScriptFX.Net.HTTPRequest for cross- browser compatible AJAX requests Supports Script transport for Cross- Domain Ajax!

Ajax/JSON private void OnOKButtonClick(object sender, EventArgs e) { Dictionary parameters = new Dictionary(); parameters["prefix"] = _prefixTextBox.Text; parameters["count"] = 5; _request = HTTPRequest.CreateRequest("CompletionList.ashx/GetItemsViaPost", HTTPVerb.POST); _request.SetContentAsJSON(parameters); _request.Invoke(new HTTPRequestCompletedCallback(OnRequestComplete), null); } private void OnRequestComplete(HTTPRequest request, object context) { if (_request == request) { string[] values = (string[])_request.Response.GetObject(); _valuesLabel.Text = values.Join(", "); }

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!

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

Quirks: Namespace references Does not work: DOMElement runner= System.DHTML.Document.GetElementById( runnerElementId); Works: Using System.DHTML; DOMElement runner= Document.GetElementById(runnerElementId);

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

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???");

Quirks: Scriptlets Scriptlet tag has to be inside a form tag –If not, nothing happens, but you don’t get an alert Inline Scriptlets use ScriptletArguments, pre-compiled ones use Dictionary

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

What’s good? Working with complex JS files is much very productive VS integration MSBuild integration Basic Documentation is great

What’s 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

Where next?

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