FieldViewResolver.GetFieldView uses File.Exists

[ronaldbarendse]

Umbraco Forms checks whether a view exists by doing a File.Exists lookup, instead of using ViewEngines.Engines.FindView(). This behavior is incompatible with the normal MVC view location logic and breaks custom view engines (e.g. RazorGenerator). It's also a performance issue, because it requires disk I/O on every check, while the built-in view locator caches the lookups.

Connected to: https://issues.umbraco.org/issue/CON-1565

Reproduction

Bug summary

I installed RazorGenerator, so I can use new C# syntax in my views, see compile errors on build and get blazing fast startup times. Because all views are compiled into the assembly, the view files itself aren't deployed (and would actually generate compile errors on startup, because the default compiler doesn't understand the new syntax).

Umbraco can find the correct (compiled) views using @Html.Partial() etc., but Umbraco Forms doesn't return the correct view when using FieldViewResolver.GetFieldView(). It seems it can't find the themed view and always returns the default...

I also tried installing Microsoft.CodeDom.Providers.DotNetCompilerPlatform to get support for the new C# syntax in the views (so the files exists and can be compiled), but then I got an error on startup from the compiler (csc.exe) with error code -532462766.

Specifics

Tested on the latest versions going from:

• Umbraco 7.11+
• Umbraco Forms 7.0.3+

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This item has been added to our backlog AB#11978

[nul800sebastiaan]

Thanks, sounds like a good idea to implement in the future! 👍

[ronaldbarendse]

@nul800sebastiaan Any progress on this?

I've checked and Umbraco Forms 8.4.2 still uses file system checks (using the IFileSystem abstraction), making rendering forms considerably slower compared to the cached ViewEngines.Engines.FindView() call. This is especially noticable on Azure-based setups (so including Umbraco Cloud), as the files are on a network share and besides disk I/O, also adds network latency!

[nul800sebastiaan]

No progress, it's still on the list of ideas to work on in the future.