KendoUI cascading dropdownlists, need value from 2

Question

I have 3 cascading dropdownlists as follows:

<p>
    <label for="categories">Catergories:</label>
    @(Html.Kendo().DropDownList()
          .Name("categories")
          .OptionLabel("Select category...")
          .DataTextField("CategoryName")
          .DataValueField("CategoryId")
          .DataSource(source => {
               source.Read(read => {
                   read.Action("GetCascadeCategories", "ComboBox");
               });
          })
    )
</p>
<p>
    <label for="products">Products:</label>
    @(Html.Kendo().DropDownList()
          .Name("products")
          .OptionLabel("Select product...")
          .DataTextField("ProductName")
          .DataValueField("ProductID")
          .DataSource(source => {
              source.Read(read =>
              {
                  read.Action("GetCascadeProducts", "ComboBox")
                      .Data("filterProducts");
              })
              .ServerFiltering(true);
          })
          .Enable(false)
          .AutoBind(false)
          .CascadeFrom("categories")
    )
    <script>
        function filterProducts() {
            return {
                categories: $("#categories").val()
            };
        }
    </script>
</p>
<p>
    <label for="orders">Orders:</label>
    @(Html.Kendo().DropDownList()
          .Name("orders")
          .OptionLabel("Select order...")
          .DataTextField("ShipCity")
          .DataValueField("OrderID")
          .DataSource(source => {
              source.Read(read =>
              {
                  read.Action("GetCascadeOrders", "ComboBox")
                      .Data("filterOrders");
              })
              .ServerFiltering(true);
          })
          .Enable(false)
          .AutoBind(false)
          .CascadeFrom("products")
    )
    <script>
        function filterOrders() {
            return {
                products: $("#filterOrders").val()
            };
        }
    </script>
</p>

This is how the controller looks like:

    public JsonResult GetCascadeCategories()
    {
        var northwind = new NorthwindDataContext();

        return Json(northwind.Categories.Select(c => new { CategoryId = c.CategoryID, CategoryName = c.CategoryName }), JsonRequestBehavior.AllowGet);
    }

    public JsonResult GetCascadeProducts(string categories)
    {
        var northwind = new NorthwindDataContext();
        var products = northwind.Products.AsQueryable();

        if (!string.IsNullOrEmpty(categories))
        {
            products = products.Where(p => p.CategoryID.ToString() == categories);
        }

        return Json(products.Select(p => new { ProductID = p.ProductID, ProductName = p.ProductName}), JsonRequestBehavior.AllowGet);
    }

The Action in the controller only takes in 1 parameter, which is whatever value that you have specify in the DataValueField() property of the dropdownlist.

However, for my 3rd dropdownlist, I want the items in it, to be dependant on BOTH the first 2 dropdownlists, and not just the one prior.

How can I get both the selected value of the 1st and 2nd dropdownlist as well from my action?

Answer 1

To send the value of the first DDL along with the value of the second DDL when the third DDL requests its data you just need to add this value to the Data function of the Read request.

e.g.

<script>
    function filterOrders() {
        return {
            categories: $("#categories").val(),
            products: $("#filterOrders").val()
        };
    }
</script>

Also change the action method signature to have one more argument

public JsonResult GetCascadeOrders(string categories,string products)