Blazor for Excel Web Add-in?

Question

Why there is no Blazor option to create Excel Web Add-ins?

Answer 1

probably because while now technically feasible, the story isn't great. Only the UI is written in Blazor, all Excel interactions (api calls) are done in javascript. the javascript code can call static Blazor methods, and would be required to send any Excel data to Blazor. As the Excel api is promise based, this means Blazor can start an async operation, but not get the results (Blazor can not await a javascript promise). That is, all jsinterop to async javascript methods (an async function or function that returns a promise) is done with InvokeVoidAsync() the javascript needs to explicitly call back to Blazor static methods when complete:

https://learn.microsoft.com/en-us/aspnet/core/blazor/javascript-interoperability/call-dotnet-from-javascript?view=aspnetcore-8.0

here is a sample excel blazor addin:

https://github.com/OfficeDev/Office-Add-in-samples/blob/main/Samples/blazor-add-in/excel-blazor-add-in/README.md