FromBody string parameter is giving null

Question

This is probably something very basic, but I am having trouble figuring out where I am going wrong.

I am trying to grab a string from the body of a POST, but "jsonString" only shows as null. I also want to avoid using a model, but maybe this isn't possible. The piece of code that I am hitting with PostMan is this chunk:

[Route("Edit/Test")]
[HttpPost]
public void Test(int id, [FromBody] string jsonString)
{
    ...
}

Maybe it is something I am doing incorrectly with postman, but I have been trying to use "=test" (as seen in other questions asked about this topic) in the value section of the body - x-www-form-urlencoded section with the key as jsonString and nothing. I have also tried using raw - text and raw - text/plain. I get the id so I know the url is correct. Any help with this would be greatly appreciated.

PostMan is set up like this currently:

POST http://localhost:8000/Edit/Test?id=111
key = id  value = 111
Body - x-www-form-urlencoded
key = jsonString  value = "=test"

Answer 1

By declaring the jsonString parameter with [FromBody] you tell ASP.NET Core to use the input formatter to bind the provided JSON (or XML) to a model. So your test should work, if you provide a simple model class

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

[Route("Edit/Test")]
[HttpPost]
public void Test(int id, [FromBody] MyModel model)
{
    ... model.Key....
}

and a sent JSON like

{
    key: "value"
}

Of course you can skip the model binding and retrieve the provided data directly by accessing HttpContext.Request in the controller. The HttpContext.Request.Body property gives you the content stream or you can access the form data via HttpContext.Request.Forms.

I personally prefer the model binding because of the type safety.