Cascading DropDownList Helper

The usage:

@using Mvc.CascadeDropDown

//First simple dropdown 
@Html.DropDownListFor(m=>m.SelectedCountry, Model.Countries,
"Please select a Country", new {@class="form-control"})

//Dropdown list for SelectedCity property that depends on selection of SelectedCountry property
@Html.CascadingDropDownListFor( 
  expression: m => m.SelectedCity, 
  triggeredByProperty: m => m.SelectedCountry,  //Parent property that trigers dropdown data loading
  url: Url.Action("GetCities", "Home"),  //Url of action that returns dropdown data
  ajaxActionParamName: "country",   //Parameter name for the selected parent value that url action receives
  optionLabel: "Please select a City", // Option label
  disabledWhenParrentNotSelected: true, //If true, disables dropdown until parrent dropdown selected
  htmlAttributes: new { @class = "form-control" }) //Html attributes

//Dropdown list for SelectedStreet property that depends on selection of SelectedCity property
@Html.CascadingDropDownListFor(m => m.SelectedStreet, m => m.SelectedCity, 
Url.Action("GetStreets", "Home"), "city", "Please select a Street", true, new { @class = "form-control" })

Versions:

v1.3.2:

• Added support for disabled options

v2.0

• Breaking change Fixed typo in disabledWhenParrentNotSelected argument name - fixed name is disabledWhenParentNotSelected
• Introduced CascadeDropDownOptions that define the behavior of the helper and allow to set callbacks for an events which happen in casccading dropdown flow such as BeforeSend, OnCompleteGetData, OnFailureGetData, OnSuccessGetData.

v2.0.1

• Fix for dropdown id resolving when using nested models (#26)

v2.0.2

• Fix for possible NullReferenceException when using nested classes in model (#29)
• URI encode drop down values prior to sending them via GET request. Fix for #30

v2.0.3

• Fix for Multiple Dropdowns dependent on same "Master" (#28)
• Fix for Selected attribute does not work on cascading drop down(#32)