andrewmilsark.com

With a background in ASP.Net web forms, the Html.CheckBox used with ASP.Net MVC did not behave how I thought it would.

For example when adding a checkbox to the View inside a table:

   1: <%=Html.CheckBox("cb" + item.player.idPlayer)%>

Firebug shows me this rendered in the html source of the page:

What is that hidden field for???

A developer on the Microsoft ASP.Net team said that this was by design so that we can properly assign a value of ‘false’ to an unchecked checkbox (link). 

I’m assuming this was the fix for the issue in the MVC 1.0 RC builds where a null value was being returning for unchecked checkboxes.

But in ASP.Net MVC 1.0, here is what the Request.Form values are (notice all checkbox inputs are listed with either a value of ‘false’ or ‘true’):

So in my case to loop through the returned inputs and grab the Player ID’s which have been checked:

Here is the controller action code to look for checked checkboxes (from Andrey Tkach on Stack Overflow):

   1: var selectedPlayerIds = new List<int>();

   2:             IEnumerable<Player> players;

   3:  

   4:             foreach (string key in Request.Form)

   5:             {

   6:                 var checkBox = String.Empty;

   7:                 if(key.StartsWith("cb"))

   8:                 {

   9:                     checkBox = Request.Form["" + key];

  10:                     if (checkBox != "false")

  11:                     {

  12:                         int id = Convert.ToInt32(key.Remove(0, 2));

  13:                         selectedPlayerIds.Add(id);

  14:                     }

  15:                 }

  16:             }

I am now able to use these playerID’s for interaction with the repository and perform interesting logic.

Tags: asp.net mvc 1.0, web development, checkbox

Javascript does not have a built in way to get querystring values easily in name, value pairs like ASP.Net.

So how do i get the “id” value in the URL  www.myurl.com/default.aspx?id=12345  ??

Here’s a javascript function which I found on multiple sites that works well.

   1: function GetQuerystringParam(name, url) {

   2:     name = name.replace(/[\[]/, "\\\[").replace(/[\]]/, "\\\]");

   3:     var regexS = "[\\?&]" + name + "=([^&#]*)";

   4:     var regex = new RegExp(regexS);

   5:     if (typeof (url) == 'undefined') url = window.location.href;

   6:     var results = regex.exec(url);

   7:     if (results == null)

   8:         return "";

   9:     else

  10:         return results[1];

  11: }

If you want to just use the browser’s current URL as the target querystring, see an example below.

   1: var value = GetQuerystringParam("id");    

Enjoy!

Tags: javascipt, querystring, asp.net, web development