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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.