Question

I am using Html.CheckBox(). The resulting HTML is:

<input id='IsMultiGraph' name='IsMultiGraph' value='true' type='checkbox'> <input name='IsMultiGraph' value='false' type='hidden'> 

On the server I have an Action which is accepting the form post information and using a custom IModelBinder to bind the form results to one of my models. Here is a snippet of the code I am running in the IModelBinder:

bool isMultiGraph; if (!bool.TryParse(bindingContext.HttpContext.Request['IsMultiGraph'], out isMultiGraph))     bindingContext.ModelState.AddModelError('IsMultiGraph', 'Invalid boolean for \'IsMultiGraph\''); //this should not ever happen unless someone is programatically posting result.IsMultiGraph = isMultiGraph; 

The problem is that since Html.CheckBox() is rendering a checkbox as well as a hidden input field if I change the state of the textbox the postback value is doubled (ie. ‘true,false’).

I understand why this is done and I’m looking for the best way to parse the current value of the CheckBox during a postback (checked = true, unchecked = false). Is there another helper method in MVC for this or should I just write my own?

Answer 1

One way is to use the GetValues method of the NameValueCollection class in order to get the first value of the array property like this:

bindingContext.HttpContext.Request.Form.GetValues('IsMultiGraph')[0]