动态/解析 Json 对象

Question

在以下代码段中，我不明白“//this failed”下的代码与“//this works”下的代码（在创建 Azure 函数时作为样板代码提供）之间的区别。 注意：我意识到不需要强制转换为对象，但 ReadAsAsync 返回对象....

public static class FunctionTest

{

    [FunctionName("TestFunction")]

    public static async Task<HttpResponseMessage> Run([HttpTrigger(AuthorizationLevel.Function, "post", Route = null)]HttpRequestMessage req, TraceWriter log)

    {

        log.Info("C# HTTP trigger function processed a request.");

        // parse query parameter

        string name = req.GetQueryNameValuePairs()

          .FirstOrDefault(q => string.Compare(q.Key, "name", true) == 0)

          .Value;

        //if nothing in the query parameter - lets' look into the body

        if (name == null)

        {

            //this fails

            dynamic abc = (object) @"{""name"":""test""}";

            string test = abc?.name;

            // this works

            dynamic data = await req.Content.ReadAsAsync<object>();

            name = data?.name;

        }

        return name == null

          ? req.CreateResponse(HttpStatusCode.BadRequest, "Please pass a name on the query string or in the request body")

          : req.CreateResponse(HttpStatusCode.OK, "Hello " + name);

    }

}