C#-将嵌套参数传递给HttpClient PostAsync

我可以使用一些帮助将参数传递到HttpClient。PostAsync()调用Please。

我的第一个例子是我成功运行的代码。。。

            HttpClient client = new HttpClient();

            // The URL of the API endpoint
            string url = "https://user.auth.xboxlive.com/user/authenticate";

            // The parameters to send in the POST request
            var values = new Dictionary<string, string>
            {
                { "param1", "value1" },
                { "param2", "value2" },
                { "param3", "value3" },
            };

            // Encode the parameters as form data
            FormUrlEncodedContent content = new FormUrlEncodedContent(values);

            // Send the POST request
            HttpResponseMessage response = await client.PostAsync(url, content);
            

但对于其他调用,我需要发送嵌套的参数。 从概念上讲,它看起来像下面的代码。 我意识到这是错误的,因为它甚至不是合法的C#语法。
那么,有人能告诉我应该做些什么来实现这一目标吗? 尽管我多年来一直是一名开发人员,但在Http方面,我还是处于年级水平。

            HttpClient client = new HttpClient();

            // The URL of the API endpoint
            string url = "https://user.auth.xboxlive.com/user/authenticate";

            // The parameters to send in the POST request
            var values = new Dictionary<string, string>
            {
                { "param1", "value1" },
                { "param2", 
                  {
                      {"param2a", "values2a"},
                      {"param2b", "values2b"},
                      {"param2c", "values2c"}
                   },
                { "param3", "value3" },
            };

            // Encode the parameters as form data
            FormUrlEncodedContent content = new FormUrlEncodedContent(values);

            // Send the POST request
            HttpResponseMessage response = await client.PostAsync(url, content);

谢谢你的帮助