ASP.NET Core Blazor WebAssembly – Single Page Applications mit C# Christian Weyer https://thinktecture.com/christian-weyer @christianweyer Co-Founder & CTO 

2 § Co-Founder & CTO at Thinktecture AG § Personal focus on § Mobile & web-based application architectures § Interoperability, cross-device § Pragmatic end-to-end solutions § Cloud-native & serverless architectures § Independent Microsoft Regional Director § Microsoft MVP for Developer Technologies & Azure ASPInsider, AzureInsider § Google GDE for Web Technologies, Angular [email protected] @christianweyer https://www.thinktecture.com ASP.NET Core Blazor WebAssembly Single Page Applications mit C# Christian Weyer 

3 § Users want: § Cross-Platform, Cross-Device § No installations § Offline (important for many use cases) § Developers think: § Web is the solution, but web is different § SPA is the solution, but SPA is different § JavaScript seems to be an issue for some .NET developers § There is existing .NET code, what to do about it? § Which technologies to choose? § JavaScript everywhere? § C# everywhere? ASP.NET Core Blazor WebAssembly Single Page Applications mit C# OK - What is the Problem? 

4 § Users want: § Cross-Platform, Cross-Device § No installations § Offline (important for many use cases) § Developers think: § Web is the solution, but web is different § SPA is the solution, but SPA is different § JavaScript seems to be an issue for some .NET developers § There is existing .NET code, what to do about it? § Which technologies to choose? § JavaScript everywhere? § C# everywhere? ASP.NET Core Blazor WebAssembly Single Page Applications mit C# OK - What is the Problem? In the frontend: Can Blazor help here? 

5 ASP.NET Core Blazor WebAssembly Single Page Applications mit C# Blazor: How does it feel, in the first place? 

6 § Automatic-Windows-to-Web-conversion-wonder-machine ™ § Next incarnation of Silverlight (as Blazor is Web-all-the-way) § JavaScript killer ASP.NET Core Blazor WebAssembly Single Page Applications mit C# What is Blazor NOT? X 

7 § Blazor is a family of web technologies § Server § WebAssembly § Blazor WebAssembly is a SPA framework § Web, SPA & distributed computing knowledge § HTML, CSS knowledge § DOM knowledge § JavaScript for DOM interaction & 3rd party integration § C# & .NET Standard for client-side logic → Full-stack C# possible ASP.NET Core Blazor WebAssembly Single Page Applications mit C# What is Blazor? Mono Runtime .NET CLR .NET Core / .NET Standard 2.1 .NET Framework Blazor WebAssembly Blazor Server Razor Components Browser (WASM / .NET / JS) Browser (JS Stub) Server (.NET) 

8 ASP.NET Core Blazor WebAssembly Single Page Applications mit C# Our Blazor Journey The Web as a Platform Blazor WebAssembly Idea & Approach Components all over SPAs with .NET Interop & Integration Comparison Data Binding & Forms Current State & Future Web Assembly .NET Razor Components ✔ 

9 ASP.NET Core Blazor WebAssembly Single Page Applications mit C# Blazor WebAssembly in the Browser Blazor DOM WebAssembly .NET Razor Components 

10 ASP.NET Core Blazor WebAssembly Single Page Applications mit C# https://caniuse.com/#feat=wasm 

11 ASP.NET Core Blazor WebAssembly Single Page Applications mit C# Blazor WebAssembly Technical Architecture Compiler Parser JIT (.NET Assemblies are interpreted) Web APIs (DOM, IndexedDb, File Storage etc.) Browser blazor. webassembly.js Blazor SPA page (.html) JS Runtime dotnet.wasm dotnet.js mscorlib.dll etc. myapp.dll * As of 28.07.2020 blazor.boot.json 

12 ASP.NET Core Blazor WebAssembly Single Page Applications mit C# Our Blazor Journey The Web as a Platform Blazor WebAssembly Idea & Approach Components all over SPAs with .NET Interop & Integration Comparison Data Binding & Forms Current State & Future Pages vs. Components HTML, CSS C# ✔ ✔ 

13 ASP.NET Core Blazor WebAssembly Single Page Applications mit C# Our Blazor Journey The Web as a Platform Blazor WebAssembly Idea & Approach Components all over SPAs with .NET Interop & Integration Comparison Data Binding & Forms Current State & Future DI Class Libraries Full Stack (APIs, Push, Security) ✔ ✔ 

14 ASP.NET Core Blazor WebAssembly Single Page Applications mit C# Our Blazor Journey The Web as a Platform Blazor WebAssembly Idea & Approach Components all over SPAs with .NET Interop & Integration Comparison Data Binding & Forms Current State & Future Data Passing Forms Validation ✔ ✔ 

15 ASP.NET Core Blazor WebAssembly Single Page Applications mit C# Our Blazor Journey The Web as a Platform Blazor WebAssembly Idea & Approach Components all over SPAs with .NET Interop & Integration Comparison Data Binding & Forms Current State & Future JS Interop PWA ✔ ✔ ✔ 

16 ASP.NET Core Blazor WebAssembly Single Page Applications mit C# Our Blazor Journey The Web as a Platform Blazor WebAssembly Idea & Approach Components all over SPAs with .NET Interop & Integration Comparison Data Binding & Forms Current State & Future Blazor Server Established SPA Frameworks ✔ 

17 ASP.NET Core Blazor WebAssembly Single Page Applications mit C# Blazor Server Blazor JS Stub DOM .NET Razor Components ASP.NET Core (Server) SignalR-based binary data exchange State, Connections etc. Browser (Client) UI Diffs Events 

✅ Full SPA architecture approach ✅ No latency, code runs locally in the browser ✅ Full support for offline scenarios ✅ Deployment: static files on web server or cloud storage; Desktop or mobile app packaging ✴ Initial download size may be large (assets cached in browser, via Service Worker) ❌ .NET Standard code is currently interpreted by special WASM-version of Mono runtime ❌ Always needs JavaScript/TypeScript, until WASM standard is being further evolved ✅ Thin Client approach for light devices ✅ Full .NET runtime on the server, not just .NET Standard ✅ No need for API-based architecture ✴ All your code is on the server ❌ Inherently stateful execution model ❌ Need for permanent physical connections ❌ No viable option to implement offline features ASP.NET Core Blazor WebAssembly Single Page Applications mit C# My Personal Comparison Blazor WebAssembly Blazor Server 18 

19 Blazor WebAssembly Angular Language C# JavaScript, TypeScript Pre-Requisites No further pre-requisites Promotes usage of RxJS Tooling Visual Studio 2019, VS Code, VS for Mac, Rider WebStorm, VS Code et. al. Packaging Your assemblies/DLLs in the browser Optimized JS via webpack Maturity Brand new, even Preview; no predecessor Very mature; lots of experience from previous versions Community Just starts to build up Very large Ecosystem OSS will build up; Various commercial vendors expected Lots of OSS; Also commercial vendors Integration 3rd party For every JS/TS library we need a proxy/shim npm universe: pick and choose; easy to integrate Dependencies WASM support in browsers - Full Stack with single tech C#, .NET Standard JS/TS (e.g. nest.js) Size Not really optimized yet; quite large Continuously improved over years Runtime performance No experience, no real numbers; .NET is interpreted; interop WASM and JS worlds Continuously improved over years; may have pitfalls ASP.NET Core Blazor WebAssembly Single Page Applications mit C# My Personal View Blazor ⇔ Angular 

20 ASP.NET Core Blazor WebAssembly Single Page Applications mit C# Our Blazor Journey The Web as a Platform Blazor WebAssembly Idea & Approach Components all over SPAs with .NET Interop & Integration Comparison Data Binding & Forms Current State & Future Status Quo Missing Features Roadmap ✔ ✔ ✔ ✔ 

21 § Blazor WebAssembly is in v1 as 3.2.0 § WASM is an MVP (and SPAs are not a target of it) § Mono WASM runtime is immature § Blazor is under ongoing development § Missing Features, e.g. § Modules, Lazy Loading § Component Model with CSS Encapsulation § AOT Builds § Better Developer Tooling (e.g. improved Debugger, Live Reload) § Roadmap § Improved & enhanced Blazor WASM in .NET 5 timeframe § AOT postponed to .NET 6 ASP.NET Core Blazor WebAssembly Single Page Applications mit C# Current State & Future 

22 § Microsoft is building a new UI framework for the browser – so… § … ask yourself § “How do we deal with Blazor?” § “Why would we pick Blazor WebAssembly over an established SPA framework?” § “Why would we choose a SPA framework, and not Blazor WebAssembly?” § … you need to check your § Team skills § Architecture § Codebase § Try it out & build Proof-of-Concepts (with experienced people) § Web Assembly & Blazor might change the game – but it may not be a game changer for you ASP.NET Core Blazor WebAssembly Single Page Applications mit C# Call-to-Action 

23 ASP.NET Core Blazor WebAssembly Single Page Applications mit C# Blazor Recap Blazor WebAssembly enables SPAs based on C# and .NET Standard. You need to know Web, SPA architectures, Security et. al. – and JavaScript! Blazor is young & immature – technical architecture, app size, missing features. The ecosystem is immature – may evolve similar to JS SPA frameworks, plus commercial vendors. The modern web with PWA & Web Components can also work and live with Blazor WebAssembly. Blazor Server might be a fit for internal applications. Stateful server-side execution model. 

Danke! Bei Fragen kontaktieren Sie mich gerne Christian Weyer https://thinktecture.com/christian-weyer @christianweyer [email protected] Demoanwendung: https://github.com/thinktecture/blazor-webassembly-demo Artikel zu Blazor, PWA, Web Components, Angular, .NET Core & mehr: https://thinktecture.com/de/newsletter 24 

25 § Blazor § https://dotnet.microsoft.com/apps/aspnet/web-apps/blazor § Running Your ASP.NET Core Blazor WebAssembly Application As A Progressive Web App (PWA) § https://www.thinktecture.com/de/blazor/progressive-web-apps-pwa/ § Re-Using Angular Components In A Blazor WebAssembly Application Using Angular Elements – Web Components Custom Elements, FTW! § https://www.thinktecture.com/de/blazor/integration-angular-elements-web-components/ § FluentValidation library § https://github.com/Blazored/FluentValidation ASP.NET Core Blazor WebAssembly Single Page Applications mit C# Resources 

ASP.NET Core Blazor WebAssembly – Single Page Applications mit C# Christian Weyer https://thinktecture.com/christian-weyer @christianweyer Co-Founder & CTO 26