MVC Entity Framework Razor Issue - asp.net-mvc

Question

I have to following code and there's a problem and I can't figure out what's the problem. Well, I have two ideas about the place where the problem may appear but I can't find a solution.
The problem is that my layout is rendered twice.
Layout.cshtml
<div id="container">
<div id="left_side"> #RenderPage("left_side.cshtml") </div>
<div id="center_side"> #RenderBody() </div>
<div id="right_side"> #RenderPage("right_side.cshtml") </div>
</div>
left_side.cshtml
#if (ViewBag.LeftColumnVisible == true)
{
#Html.Action("GetCategories", "Products");
}
GetCategories method from Products controller
public ActionResult GetCategories()
{
List<Categories> categories = db.Categories.ToList();
...
return View();
}
GetCategories.cshtml
#foreach (System.Collections.DictionaryEntry de in ViewBag.LeftColumnContent)
{
<div> #((Ads.Models.Categories)(de.Key)).Name; </div>
}
It enters the get categories and renders the content.
The problem for rendering twice may be at this line
#Html.Action("GetCategories", "Products"); or when it calls View(). If I comment the line, my layout will be rendered only once.

Answer 1

I'd say there are a couple of issues with your code. First of all, if left_side.cshtml/right_side.cshtml are partial views then you want to be using
#Html.RenderPartial("view")
to render them and not #RenderPage - although #RenderPage will work it's better from a readability point of view to understand exactly what the type of view it is you are working with.
Secondly, if your GetCategories view is a partial view you want to be returning a PartialView and not a View i.e.
public ActionResult GetCategories()
{
...
return PartialView();
}