在尝试从Web API获取JSON数据的教程时，我偶然发现了此错误，而视频没有遇到此错误

Question

All it tells me to do is change GetResponse to either: EndGetResponse(), BeginGetResponse() or GetResponseAsync()

The error message reads: 'HttpWebRequest' does not contain a definition for 'GetResponse' and no extension method 'GetResponse' accepting a first argument of type 'HttpWebRequest' could be found (are you missing an assembly reference?)

and I'm getting an error on this specific section:

using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
        {
            if(response.StatusCode != HttpStatusCode.OK)
            {
                throw new Exception("error code:" + response.StatusCode.ToString());

This was the code in said video:

public enum httpVerb
{
    GET,
    POST,
    PUT,
    DELETE
}

class RestClient
{
    public string endPoint { get; set; }
    public httpVerb httpMethod { get; set; }

    public RestClient()
    {
        endPoint = string.Empty;
        httpMethod = httpVerb.GET;
    }

    public string makeRequest()
    {
        string strResponseValue = string.Empty;

        HttpWebRequest request =      (HttpWebRequest)WebRequest.Create(endPoint);

        request.Method = httpMethod.ToString();

        using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
        {
            if(response.StatusCode != HttpStatusCode.OK)
            {
                throw new Exception("error code:" + response.StatusCode.ToString());
            }

            using (Stream responseStream = response.GetResponseStream())
            {
                if(responseStream != null)
                {
                    using (StreamReader reader = new StreamReader(responseStream))
                    {
                        strResponseValue = reader.ReadToEnd();
                    }
                }
            }
        }

        return strResponseValue;
    }
}

}

Answer 1

Without knowing the specifics of the video or what the rest of your code/project look like I can only go by the error:

HttpWebRequest' does not contain a definition for 'GetResponse' and no extension method 'GetResponse' accepting a first argument of type 'HttpWebRequest' could be found (are you missing an assembly reference?)

Have you checked your assembly references to see if you have a reference to System.Net?

EDIT

It seems like you might be confusing using statements with assembly references. Although your class file contains using statements to System.Net, your project itself might not have a reference to the System.Net dll.

Here is a quick guide on how to manage those references in Visual Studio.

As a quick check:

1. Find the References section in your Visual Studio project.
2. Right Click `References'
3. Click Add Reference
4. In the Assemblies > Framework section verify that System.Net is checked

EDIT #2

It looks like you created a UWP project instead of the video's perscribed Windows Form project type. The reason you are getting errors in your code is because the GetResponse() method of HttpWebRequest cannot be used in UWP projects. This answer explains in a bit more detail.