MVC3 Html.BeginForm - passing arguments as RouteValueDictionary fails

Question

I have a multi-step setup process where I would like to pass query string arguments appended to the URL only if they are relevant.

http://localhost:6618/Account/Prof

Answer 1

args was generated by a filter, and is a RouteValueDictionary

That's the key point here. In this case make sure you are using the correct overload of the BeginForm method:

@using(Html.BeginForm(
    "Profile", 
    "Account",   
    args, 
    FormMethod.Post, 
    new RouteValueDictionary(new { @class = "mainForm" })
))
{
    ...
}

Notice the last argument? It must be an IDictionary for this to work.

In your example it is this overload that gets picked up. But since you are passing a RouteValueDictionary for the routeValues parameter instead of an anonymous object it gets messed up.

So, you should either have both routeValues and htmlAttributes as dictionaries or both as anonymous objects.