Asp.net Web API - return data from actionfilter

Question

I want to return a json object from the wep api actionfilter. How can I achieve this?

I can return the object from action but I need to return some data from the actionf

Answer 1

All you need is to assign the Response:

public class MyActionFilterAttribute: ActionFilterAttribute
{
    public override void OnActionExecuting(HttpActionContext actionContext)
    {
        actionContext.Response = actionContext.Request.CreateResponse(
            HttpStatusCode.OK, 
            new { foo = "bar" }, 
            actionContext.ControllerContext.Configuration.Formatters.JsonFormatter
        );
    }
}

Assuming the following controller action:

[MyActionFilter]
public string Get()
{
    return "OK";
}

this custom action filter will short-circuit the execution of the action and directly return the response we provided.

Answer 2

Just throwing this out there in case anyone else comes here like me and doesn't find an answer to their problem:

You may be using the wrong import - You have 2 options:

• System.Web.Http.Filters
• System.Web.Mvc (or System.Web.Http.Mvc)

Courtesy of Troy Dai from this question: Why is my ASP.NET Web API ActionFilterAttribute OnActionExecuting not firing?

Answer 3

you can use HttpResponseMessage to create the response like that

var output =  new Result() { Status = Status.Error.ToString(), Data = null, Message = arr };
actionContext.Response = new HttpResponseMessage {
                Content = new StringContent(JsonConvert.SerializeObject(output), Encoding.UTF8, "application/json"),
                StatusCode = HttpStatusCode.OK
            };