CheckboxList

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FormHelper allows you to generate a list of checkboxes associated with a data source. It is also able to pre-check the checkboxes based on the initial selection set. Make sure you have read the How FormHelper works with sets document.

Simple example

Listing checkboxes requires a state object. To create it you invoke CreateCheckboxList which returns a CheckboxList instance. A CheckboxList is enumerable and exposes an Item method. You must enumerate the elements and while doing it invoke Item which returns the checkbox element.

Consider the following action code:


public void Index()
{
    // data source
    PropertyBag["primenumbers"] = new int[] { 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47 };
    
    // initial selection
    PropertyBag["selectedPrimes"] = new int[] { 11, 19, 29 };
}

The code on the view to use it would be:


<p>
#set($items = $FormHelper.CreateCheckboxList("selectedPrimes", $primenumbers))

#foreach($elem in $items)
  $items.Item()  $elem   <br/>
#end
</p>

Complex objects

With complex objects you must care to specify the value parameter so the FormHelper can generate proper html elements.

Consider the following action code:


public void Index()
{
    // data source
    Category[] categories = new Category[] 
    { 
        new Category(1, "Music"), 
        new Category(2, "Humor"), 
        new Category(3, "Politics")  
    };
    PropertyBag["categories"] = categories;
    
    // initial selection
    Blog blog = new Blog();
    blog.Categories = new Category[] { new Category(2, "Humor") };
    PropertyBag["blog"] = blog;
}

The Category class above has an Id property and Name property. So here is how the view would use it:


<p>
#set($items = $FormHelper.CreateCheckboxList("blog.categories", $categories, "%{value='Id'}"))

#foreach($elem in $items)
  $items.Item()  $elem.Name   <br/>
#end
</p>

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CheckboxList

Simple example

Complex objects