Web API parameter is always null

Question

I have the following method in my Web API:

[AcceptVerbs("POST")]
public bool MoveFile([FromBody] FileUserModel model)
{
    if (model.domain == "abc")
    {
        return true;
    }
    return false;
}

The FileUserModel is defined as:

public class FileUserModel
{
    public string domain { get; set; }
    public string username { get; set; }
    public string password { get; set; }
    public string fileName { get; set; }
}

I'm trying to call this through Fiddler but whenever I do the model is always set to null. In Fiddler I've sent the composer to use POST, the url is there and correct as the debugger in Visual Studio breaks when called. The Request I've setup as:

User-Agent: Fiddler 
Host: localhost:46992 
Content-Length: 127 
Content-Type: application/json

The Request Body as:

"{
  "domain": "dcas"
  "username": "sample string 2",
  "password": "sample string 3",
  "fileName": "sample string 4"
}"

But whenever I run the composer when the debugger hits the breakpoint it always shows model is null.

Answer 1

The problem you have is you are posting the JSON data with surrounding double quotes. Remove them and it should work.

Also fix the missing comma:

{
  "domain": "dcas",
  "username": "sample string 2",
  "password": "sample string 3",
  "fileName": "sample string 4"
}

Answer 2

You're missing a , in the request that you're sending. Also, because of the enclosing double quotes, you're actually sending a JSON string, not a JSON object. Removing the quotes and adding the comma should fix your problem.

{
    "domain": "dcas", // << here
    "username": "sample string 2",
    "password": "sample string 3",
    "fileName": "sample string 4"
}

Also, since you're posting a model, you don't need the [FromBody] attribute.

[AcceptVerbs("POST")]
public bool MoveFile(FileUserModel model)
{
    if (model.domain == "abc")
    {
        return true;
    }
    return false;
}

That should be just fine. For more information on this, see this blog.

Answer 3

You need to make ajax call like below

$(function () {
    var FileUserModel =    { domain: "dcas", username: "sample string 2", 
            password: "sample string 3", fileName: "sample string 4"};
    $.ajax({
        type: "POST",
        data :JSON.stringify(FileUserModel ),
        url: "api/MoveFile",
        contentType: "application/json"
    });
});

Dont forget to mark content type as json and on server side api code

[HttpPost]
public bool MoveFile([FromBody] FileUserModel model)
{
    if (model.domain == "abc")
    {
        return true;
    }
    return false;
}

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