The call is ambiguous between the following method or properties in ASP.NET MVC RenderAction

Question

The call was working fine until I installed ASP.NET MVC 1.0 RTM.

Error: CS0121: The call is ambiguous between the following methods or properties

code snippet

<%Html.RenderAction("ProductItemList", "Product"); %>

Action Method

public ActionResult ProductItemList()
{
  return View("~/Views/Product/ProductItemList.ascx", _repository.GetProductList().ToList());
}

Politic

Answer 1

You have two action methods with the same signature, and the RenderAction cannot decide which to use. You need to somehow make the actions unique.

I usually see this when there is a Action for a GET and POST, both without and parameters. An easy workaround is to add FormCollection form as the parameter of POST.

[HttpGet]
public ActionResult ProductItemList()
{
    //GET
}

[HttpPost]
public ActionResult ProductItemList(FormCollection form)
{
    //POST
}

Trelliswork

I only have one method in the same controller. But I solved the problem. For MVC RTM, RenderAction cyntax is different than the previous. It is <%Html.RenderAction<namespace.controllers.controllerName>(p => p.ProductItemList());%> – Politic

RTM? Which version of MVC are you using. For 2.0 the syntax you had would have looked for an ProductItemList action in the Product controller. Glad its working for you. – Trelliswork

RenderAction() is invoked from the View that is calling it. The [HttpGet] and [HttpPost] attributes are to be used for requests that are coming in from an actual Http request. RenderAction is inherently being called as a child request (not directly from Http). – Yolanda

@Steve, completely understand. I put the attributes there for clarification on my explanation of separation of ambiguous methods. – Trelliswork