无法访问从 WebClient.UploadValues() 返回的 C# object 属性

Question

Sending a WebClient() request to a Web API, my API call is returning with data which I am deserialising with JsonConvert.DeserializeObject().

The object then has properties which I cannot seem to reference.

var coursesParams = new NameValueCollection();

coursesParams.Add("grant_type", "password");
coursesParams.Add("client_id", "ContentUpload");
coursesParams.Add("client_secret", "2dfe381b4e620fff9b4fa05997e26d141d9c2c6d");
coursesParams.Add("username", "isadmin");
coursesParams.Add("password", "xxxxxxxxx");

WebClient coursesRequest = new WebClient();

coursesRequest.Encoding = Encoding.UTF8;
coursesRequest.Headers.Add("Authorization", "Bearer " + x.access_token);
coursesRequest.Headers.Add("Content-Type", "application/x-www-form-urlencoded");
coursesRequest.Headers.Add("Accept-Language", "en-US");
coursesRequest.Headers.Add("Accept", "text/html, application/xhtml+xml, */*");
coursesRequest.Headers.Add("User-Agent", "Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0)");

var coursesData = coursesRequest.UploadValues("https://xxx.yyyyyyyyyy.com/api/course/courses", "POST", coursesParams);

var y = JsonConvert.DeserializeObject(Encoding.ASCII.GetString(coursesData));

System.Console.ReadKey();

When I pause the program and examine the y object in the debugger, it shows properties, but I cannot reference any of them. Screen image:

And, any attempt to reference (or read) these properties results in an error:

y.ChildrenTokens
error CS1061: 'object' does not contain a definition for 'ChildrenTokens' and no accessible extension method 'ChildrenTokens' accepting a first argument of type 'object' could be found (are you missing a using directive or an assembly reference?)
y.Count
error CS1061: 'object' does not contain a definition for 'Count' and no accessible extension method 'Count' accepting a first argument of type 'object' could be found (are you missing a using directive or an assembly reference?)

What am I doing (or seeing) wrong? Are these properties simply not accesssible? Or am I referencing them incorrectly?

Answer 1

In C#, you can't access properties that are not defined on a type. You can see the properties in the debugger because that is the raw text input. But since you did not specify a type to deserialize to, the DeserializeObject method is simply creating plain object instances - and object does not contain definitions for any of your properties (ChildrenTokens, Count, etc).

To fix this, you should create a class with properties that match the schema of the JSON that you are parsing. This might be a good start:

public class CourseData {
    public List<Course> courses { get; set; }
    public string item_count { get; set; }
    public bool success { get; set; }
}
public class Course {
    public int course_id { get; set; }
    public string code { get; set; }
    public string course_name { get; set; }
}

Fill in the remaining properties, and then deserialize like this:

// Option 1
var y = JsonConvert.DeserializeObject<CourseData>(Encoding.ASCII.GetString(coursesData));

// Option 2
CourseData y = JsonConvert.DeserializeObject(Encoding.ASCII.GetString(coursesData));