We are happy to announce the release of WebSharper 4.5.5.

Download the project templates for .NET Core SDK: dotnet new -i WebSharper.Templates::4.5.5.283

Or use the extension for Visual Studio 2017: http://websharper.com/installers/WebSharper.4.5.5.283.vsix

The main highlight of this release is the addition of dynamic templating: the capability to fill template holes using their name as a string, rather than a strongly typed method. This is done using the .With() method.

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open WebSharper.UI.Templating

type MyTemplate = Template<"<div>${SayWhat} ${ToWhom}!</div>">

let helloWorld =
    MyTemplate()
        .SayWhat("Hello")        // Usual strongly typed fill
        .With("ToWhom", "world") // New dynamic fill
        .Doc()

Accompanying this is a new type DynamicTemplate which is not a provided type, and therefore can only be filled using .With().

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open WebSharper.UI.Templating

let helloWorld =
    DynamicTemplate("<div>${SayWhat} ${ToWhom}!</div>")
        .With("SayWhat", "Hello")
        .With("ToWhom", "world")
        .Doc()

Note that this feature is only available on the server side for now.

Full release notes:

WebSharper

Fixes

• #1034 Router: accept an empty final fragment if a route expects a string.

WebSharper.UI

Features

• #175 <ws-*> template instantiation is now implemented on the server side.
• #200 Server-side templating: Var<string> holes are fully bound on the client side, including dynamically bound to ${Text} holes with the same name in the same template.
• #201 Add dynamic holes for server-side templates. The method .With("holeName", value) now fills the given hole with the given value. An error is raised at runtime if the type of value is incompatible with the hole.
• #201 Add DynamicTemplate as a non-provided type similar to the provided Template, with the following differences:
  • DynamicTemplate is (for now) server-side only.
  • DynamicTemplate must be instantiated with a string argument.
  • DynamicTemplate holes can only be filled with .With().
  • DynamicTemplate instantiation can only be finished with .Doc().

Fixes

• #187 C# templating: the build task doesn't write the generated C# file if it would be identical to the existing file. This makes it possible to use a file system watcher such as dotnet watch without running into an infinite loop.

Happy coding!