无法使用Postasync将表单数据发送到Web API

Question

I am trying to send sourceFile value to web api. But in API i am receiving is null

var formVars = new Dictionary<string, string>();
formVars.Add("sourceFile", "Helloo");

HttpContent content = new FormUrlEncodedContent(formVars);                   

var result = client.PostAsync("ImageApi/Compare", content).Result;
string resultContent = result.Content.ReadAsStringAsync().Result;
return Content(resultContent);

API code

[HttpPost()]
public ActionResult Compare(string sourceFile)
{
   return Ok(sourceFile);
}

I am using DotNet core 2.0

Answer 1

you need to await the result, do not try to access .Result yourself. The call would not have completed at that point.

you need to use something like this:

HttpContent content = new FormUrlEncodedContent(formVars);                   

var result = await client.PostAsync("ImageApi/Compare", content);
result .EnsureSuccessStatusCode();
string responseBody = await result.Content.ReadAsStringAsync();

This is based on your code and hasn't been tested but should set you on the right path to get this working. Don't ever try to do async stuff by accessing .Result.

One more thing, you need to use a model as well.

create a model class, which has all the properties you add in your dictionary.

in your case it will be something like :

public class MyModel{
     public string sourceFile { get ;set; }
}

your controller becomes:

[HttpPost()]
public ActionResult Compare([FromBody]MyModel model)
{
   return Ok(model.sourceFile);
}