Regarding binding Cascaded DropdownList

Guest User

Hello,

I am using OrmLite technology in my MVC code. I need help to bind selected Cascaded DropdownLists (Country, State, City) for a logged in user which is saved on Signup Form.

Below is my code (this code binds only Country):

var countrystring = "SELECT Id, CountryName FROM CountryMaster where Id ='" + countryid + "'";

DataSet ds = new DataSet();

List li = new List();

DataTable dt = new DataTable();

dt = objdal.MyMethod(countrystring.ToString());

List list = new List();

foreach (DataRow row in dt.Rows)

{

list.Add(new SelectListItem { Text = Convert.ToString(row.ItemArray[1]), Value = Convert.ToString(row.ItemArray[0])});

}

ViewBag.country = list;

Here it binds Country based on CountryId, but another CountryNames is not getting bound.

Thanks in advance.

3 Replies

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Vincent Maverick Durano8y ago
You can still follow the same concept of binding your DropDownList. However the idea now is to get the data from database based from the user id.

The first you need to do is ensure that you are storing the id of the country that was selected by the user in database.

Then you create a class the will hold the following properties:
public class CountryList
{
        public int? SelectedCountryID { get; set; }
        public IEnumerable Countries { get; set; }
}
Once you have that, you will then create a class that will be used in your Edit View. For example:
public class MyEditViewModel{
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public CountryList CountryList { get; set; }
}
The class above will contain all the properties you need for your View. Keep in mind that we've added the CountryList property there which has a SelectedCountryID property.
Now in your Controller Action, you can fill that class with data from your database. For example:
public ActionResult Edit(int id) {
    var data = GetDataFromDataBase(id);
    MyEditViewModel model = new MyEditViewModel();

    if(data.Any()){
        model.FirstName = data.First().FirstName;
        model.LastName = data.First().LastName;
        model.CountryList = new CountryList{
            SelectedCountryID = data.First().CountryID,
            CountryList = GetAllListOfCountriesFromDatabase();
        }
        }

    return View(model);

}
Then in your View, you can do something like this to populate your DropDownList:
@Html.DropDownListFor(o => o.CountryList.SelectedCountryID,
                       new SelectList(Model.CountryList.Countries, "CountryID", "CountryName"),
                       "",
                       new { id = "ddlCountry", @class="form-control" })
Guest User8y ago
Hey Vincent Maverick Durano,
Thanks for reply.
I am able to bind cascaded dropdownlist on Page Load. I need help to bind it on Edit View (i.e When User is logged in to dashboard, it should fetch those dropdownlist value which User saved on Register or Signup Form)
Vincent Maverick Durano8y ago
There are tons of examples that demonstrate how to implement cascading dropdownlist with ASP.NET MVC. You just have to do a simple search at google for that. Here's one I found on this site: https://www.c-sharpcorner.com/article/creating-simple-cascading-dropdownlist-in-mvc/