rest - Calling a web service not from same origin with Web Assembly

Question

I'm experimenting with Blazor WebAssembley (.Net 5), calling my rest web api (built a while ago using .netcore 2.0.0).

I am running the code against a debug version of the web service hence the localhost url on port 51259.

When the code gets hit I get an exception that I cannot understand:

Unhandled exception rendering component: TypeError: Failed to fetch
System.Net.Http.HttpRequestException: TypeError: Failed to fetch

I have setup CORS on the web service in the form of:

public void ConfigureServices(IServiceCollection services)
{
    services.AddMvc();

    services.AddCors(c =>
   {
       c.AddPolicy("AllowOrigin", options => options.AllowAnyOrigin().AllowAnyHeader().WithMethods("GET, PATCH, DELETE, PUT, POST, OPTIONS"));
   });

}

Client side Blazor WebAssembley

@code {
private Models.MyFooObject fooObject = new Models.MyFooObject();

private async Task UpdateDatatheme()
{
    //ERROR HERE
    fooObject = await Http.GetFromJsonAsync<Models.MyFooObject("http://localhost:51259/service/myfooObject/0001"); 
}

Can anyone help - I'm out of ideas.

Answer 1

等待大神解答