ASP.Net Forms HttpClient PostAsync 无响应，无错误消息

Question

I have this code:

using (var client = new HttpClient())
{
    var values = new Dictionary<string, string>
        {
            {"site_id","001"},
            {"apikey","abc01201az1024"},
            {"trans_id","45364136"},
        };

    // Get the parameters in the url encoded format
    var content = new FormUrlEncodedContent(values);

    //Send request
    var response = await client.PostAsync(url, content);

  DataRoot<Transaction> outPut = null;
                if (response.IsSuccessStatusCode)
                {
                    //Get Response
                    var result = await response.Content.ReadAsStringAsync();
                    JsonConvert.DeserializeObject<DataRoot<Transaction>>(result);
                }

                return outPut;
}

In the debug mode at this stage, the code does not produce any response, no error code but stops running:

//Send request
var response = await client.PostAsync(url, content);

Answer 1

there could be a better way but this solved my problem. Call your method from another one using wait:-

    public static async Task<string> AuthenticateUser()
    {
        var t = Task.Run(() => ClassObject.AuthenticateUser("me"));
        t.Wait();

        Console.WriteLine(t.Result);
        Console.ReadLine();
        return "ok";
    }

Answer 2

Using await like this, can end up in a deadlock.

You can use ConfigureAwait(false) in async methods for preventing such a deadlock.

Update code to:

var response = await client.PostAsync(url, content).ConfigureAwait(false);

This will solve the issue.

Answer 3

Are you sure that it isn't actually returning the response and continuing execution? Because the client.PostAsync() call is awaited execution may continue on a different thread. Therefore, if you're just debugging line by line (via F10 or similar) it may appear that the method never returns; in actuality the entire method has finished execution and your program is running.

You may need to add another breakpoint in the method (after the PostAsync method call). When the PostAsync method returns on a different thread, your debugger should hit the next breakpoint.