In Blazor webassembly is there a way to enforce the use of Newtonsoft.Json serlialization for httpclient and methods such as GetJsonAsync, PostAsJsonAsync etc.
Or the only way is to write helper methods and use GetAsync and then serialize the response manually using Newtonsoft.Json?
is there a way to enforce the use of Newtonsoft.Json for ... PostAsJsonAsync etc.
No. This has been shifting around a bit lately, especially for Blazor. But the System.Net.Http.Json.HttpClientJsonExtensions are now directly dependent on System.Text.Json, not pluggable.
So yes, you will have to write your own helpers, not too big a deal. The linker might even remove the System.Text.Json classes in a Release build, I'm not sure.
But the counter question is of course why you need this? NewtonSoft is legacy from now on and if you really have incompatible data maybe ask if you can resolve this with some System.Text options.
