C# ASP.NET MVC 2 basic routing

Question

I'm quite new to ASP.NET and C# and I'm having some issues with my routing. Was hoping someone would be so kind to help me out.

A user is supposed to give 3 parameters (string, bool, bool). So I have a small form on my index page:

  <% using (Html.BeginForm("search", "Home")) { %>
        <label >Name: </label><br />
        <input type="text" id='ml' name='ml' /><br />
        <label >Sort members alphabethic? </label> <input type="checkbox" id='sortalph' name='sortalph' /><br />
        <label >Number the list? </label><input type="checkbox" id='number' name='number' /><br />
        <input type="submit" value='Submit'/>
   <% } %>

Global.asax.cs is set up like this:

  routes.MapRoute(
            "Default", // Route name
            "{controller}/{action}", // URL with parameters
            new { controller = "Home", action = "Index"} // Parameter defaults
        );
        routes.MapRoute(
         "Search", // Route name
         "{controller}/{action}/{ml}/{sortalph}/{number}", // URL with parameters
         new { controller = "Docent", action = "Search" } // Parameter defaults
     );

The start of the Search method in my HomeController looks like this:

public ActionResult Search(string ml,  bool? sortalph,  bool? number)
{
    if (sortalph == null)
    {
        sortalph = false;
    }
    if (number == null)
    {
        number = false;
    }

When I debug sortalph and number are always null. I'm not sure why.

@dan, I use nullables frequently too, so that I can distinguish between a clean url/post with the parameter missing (and thus use a default that could be 'true') and when it was actually passed deliberately 'false' or '0' without having to consult the valueprovider — Andras Zoltan, Aug 05 '11 at 06:26

score 1 · Accepted Answer · answered Aug 04 '11 at 11:54

You don't need to add a special route for these since they are simply going to be added by the browser into the query string, or into the post body if the form is a post, when the form is submitted.

So, if the browser does a GET, then it actually forms the url /home/search?ml=[whatever]&sortalph=[whatever]&number=[whatever]. MVC automatically maps the parameters, by name, to those values from the query string.

If you comment out the route you should find that it will all start working.

score 1 · Answer 2 · answered Aug 04 '11 at 11:57

The problem is strictly related to two factors:

Your bool parameters on the action method shouldn't be nullable. Use bool and not bool?
Your checkboxes on the html should have value="true" so when they are checked, the correct value will be sent and the property will get the right value.

Apart from that, you could use html helper methods instead of plain html to create your form. Your html has many flaws, like labels missing the for attribute, etc.

Also since it's a search form, you should use an HTTP GET method to make the search result indexable and bookmarkable, but you're not specifing it and the default overload of BeginForm will render a form tag using HTTP POST method.

C# ASP.NET MVC 2 basic routing

2 Answers2