Cascading DropDown List in MVC 4

asp.net, asp.net-mvc, asp.net-mvc-4, cascadingdropdown, entity-framework

Solution

The following form is a situation where based upon the selected gender (Male or Female), the titles for the gender are displayed (Mr. for Male, Mrs. for female).

Using the `Ajax.Begin()` helper you can post back to the controller and return values to the view.

All of the data is hard-coded so please forgive the manual adding of the information.

View - Form.cshtml

<fieldset>
    <legend>Form</legend>
    @* This will post to the BindTitles method in the Form Controller *@
    @using (Ajax.BeginForm("BindTitles", "Form", new AjaxOptions
    {
        HttpMethod = "POST"
    }))
    {  
        <p>
            @Html.DropDownList("Genders")
        </p>        
        <p>
            <input type="submit" value="Submit" />
        </p>
    }
    <p>
        @Html.DropDownList("Titles")
    </p>
</fieldset>

Controller - FormController

    public ActionResult Form()
    {
        List<string> genderList = new List<string>();
        genderList.Add("Male");
        genderList.Add("Female");
        ViewBag.Genders = new SelectList(genderList);
        ViewBag.Titles = new SelectList(new List<string>());
        return View();
    }

    [HttpPost]
    public ActionResult BindTitles(string genders)
    {
        List<string> titles = new List<string>();
        if (genders == "Male")
        {
            titles.Add("Mr.");
            titles.Add("Sr.");
        }
        else
        {
            titles.Add("Ms.");
            titles.Add("Mrs.");
        }
        ViewBag.Titles = new SelectList(titles);
        List<string> genderList = new List<string>();
        genderList.Add("Male");
        genderList.Add("Female");
        ViewBag.Genders = new SelectList(genderList);
        return View("Form");
    }

Problem

I have a ASP.NET MVC 4 project with EF I have a table with Parteners. This table has 2 types of parteners : agents(part_type=1) and clients(part_type=2). In an Create view I have the first DropDownList that shows all my agents, a button and the second DDL that shows all my clients that correspond to the selected agent. Q1 : What button shoud I use ? , , @Html.ActionLink() ? Create.cshtml ``` <div class="editor-field"> @Html.DropDownList("idagenti", ViewData["idagenti"] as List<SelectListItem>, String.Empty) </div> @*a button*@ <div class="editor-label"> @Html.LabelFor(model => model.id_parten, "Client") </div> <div class="editor-field"> @Html.DropDownList("id_parten", String.Empty) @Html.ValidationMessageFor(model => model.id_parten) </div> ``` OrdersController.cs ``` public ActionResult Create(int? id) // id is the selected agent { var agqry = db.partener.Where(p => p.part_type == 1).Where(p => p.activ == true); var cltqry = db.partener.Where(p => p.part_type == 2).Where(p => p.activ == true); List<SelectListItem> idagenti = new List<SelectListItem>(); foreach (partener ag in agqry) { idagenti.Add(new SelectListItem { Text = ag.den_parten, Value = ag.id_parten.ToString() }); } if (id != null) { cltqry = cltqry.Where(p => p.par_parten == id); } ViewData["idagenti"] = idagenti; ViewBag.id_parten = new SelectList(cltqry, "id_parten", "den_parten");// } ``` Q: How can I pass the selected agent id from the first DDL to my controller ?

Original source

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