这里的答案是是，隐式身份验证流程可以请求范围就好了.我的问题与我使用的 OAuth 组件有关.该组件以静默方式对范围参数的值进行 URL 编码，该值被 Instagram 身份验证端点拒绝.我更新了组件 (Xamarin.Auth) 以容纳非编码范围参数并发出拉取请求.

The answer here is that YES, scopes can be requested by implicit auth flow just fine. My problem was related to an OAuth component that I was using. The component was silently URL-encoding the value of the scope param, which was rejected by the Instagram auth endpoint. I updated the component (Xamarin.Auth) to accomodate a non-encoded scope param and issued a pull request.

感谢@krisak 提供了一个我可以测试的有效网址.

Thanks to @krisak for providing a working URL that I could test.