Web Api，ajax和内容类型

Question

I would like to understand a little better about WebApi in Net and how is the correct way to called it with ajax. Little of info about my development environment: I am using .net 4.0 and visual studio 2010 and Jquery.

Model:

public class TestForm
{
    public string FirstName { get; set; }
}

WebApi:

public class TestpController : ApiController
{
    [HttpPost]
    public HttpResponseMessage Post(TestForm form)
    {
        string jose = "jose";
        return Request.CreateResponse(HttpStatusCode.OK, "yay");
    }
}

Client side:

V1 (doesnt work, return error 405 ):

$.ajax({
    url: "http://xxx/api/Testp",
    type: "POST",                   
    data: JSON.stringify({ FirstName: "Jose" }),                
    dataType: 'json',
    contentType: "application/json; charset=utf-8",                                 
    success: function(data) {
        console.log("success");
    },
    error: function (xhr, errorType, exception) {
        console.log("error");
    }
});

V2 (works):

$.ajax({
    url: "http://xxx/api/Testp",
    type: "POST",                   
    data: { FirstName: "Jose" },                
    dataType: 'json',
    success: function(data) {
        console.log("success");
    },
    error: function (xhr, errorType, exception) {
        console.log("error");
    }
});

Why do I get an error when I add contentType: "application/json; charset=utf-8" and change the data to JSON.stringify({ FirstName: "Jose" }), but it works when I removed the content type and send a object in data option.

Answer 1

Short answer lies in the output of these alerts:

alert(JSON.stringify({FirstName :"Jose"}));
alert({FirstName :"Jose"});

The first one gives you a string, the second one gives you an object.

Your method:

public HttpResponseMessage Post(TestForm form)

Accepts an object and not a string. So when you post a string, .NET Framework is not able to find a method which can process a string, hence returns 405.