on 12/24/2017 6:21 PM

WebSharper 4.1 is now available on NuGet, and as a vsix installer on the WebSharper website.

New and updated documentation: WebSharper 4.1 for C# and WebSharper 4.1 for F#.

See some new features live at Try WebSharper: in C# and in F#.

The release notes are also on GitHub.

New features

  • Server-side event handlers and ctx.ClientSide can take any fixed F# quotation now and translates it to JavaScript.
  • New implementation for WebSharper.Sitelets.Router type, fully composable and also working on the client-side. WebSharper.UI adds helpers to use it for client-side routing. This allows generating safe links on the client for server-side endpoints, also on the server to states handled by the client.

See the details of Sitelet and Router features in the C# and F# documentation.


  • WebSharper.UI.Next has been renamed to WebSharper.UI, affecting both package and namespace naming. For C# projects, an additional package reference for WebSharper.UI.CSharp is needed, and .CSharp has been removed from all namespace names, so now no extra usings are needed to get the C#-oriented extension methods. A compatibility package WebSharper.UI.Next 4.1 still exists for immediate back-compatibility, switching to WebSharper.UI is recommended for new features and fixes.
  • For composing HTML in F#, the ...Attr family of functions have been renamed to match just the name of the tag, while the previous functions taking no Attr list have been removed. So previous div [text "Hello"] becomes div [] [text "Hello"] with WebSharper.UI.
  • An nice and easy syntax is available for creating reactive values. If x and y are both Var<int> or View<int> then V(x.V + x.Y) is eqivalent to using View.Map2 (+). Also within F# text or Attr. functions and any C# HTML combinators, the logic for V(...) is applied automatically, so no extra wrapping is needed.
  • Template types (created either by the C# code generator or the F# type provider) have a new .Vars property, exposing all the variables that has been bound to inputs in the template. If you specify no binding, a Var will be implicitly created for the input.
  • The IRef type has been removed and Var is now an abstract class.

See the details of UI features in the C# and F# documentation.


  • Fix using <UseDownloadedResources>True</UseDownloadedResources> in web.config, now local script links are correct for any sub-page.
  • Expanded WebSharper.Testing to expose more equality test alternatives provided by QUnit.
  • Better handling of F# trait calls (using a member constraint inside an inline function). Now an overloaded method is resolved based on signature.
  • Optimization of remoting protocol: array of types are not included when it is empty.

Breaking changes

  • Attributes previously in WebSharper.Sitelets namespace and assembly are now in WebSharper namespace and in WebSharper.Core.dll.
  • A Sitelet's Router field is now of type IRouter, compatible in capabilities with the old Router record. The new Router type offers more combinators and is implementing IRouter.

IntelliFactory Offices Copyright (c) 2011-2012 IntelliFactory. All rights reserved.
Home | Products | Consulting | Trainings | Blogs | Jobs | Contact Us
Built with WebSharper