Countries and cities drop down manipulation in asp.net MVC project

asp-mvc-country-cities-drop-down-ajax.md

1. Create Razor Page: Create a new Razor Page named Index.cshtml or any other relevant name.

2. Design the UI: In your Razor Page's HTML markup, create two dropdown lists - one for countries and one for cities:

   <select id="countryDropdown">
       <option value="">Select Country</option>
       <!-- Populate countries dynamically if needed -->
   </select>
   
   <select id="cityDropdown">
       <option value="">Select City</option>
       <!-- Cities will be populated dynamically based on selected country -->
   </select>

3. Implement AJAX Call: Use jQuery to make an AJAX call to fetch cities based on the selected country:

   <script>
   $(document).ready(function() {
       $('#countryDropdown').change(function() {
           var selectedCountry = $(this).val();
           $.ajax({
               url: '/YourController/GetCities', // Endpoint to fetch cities
               method: 'GET',
               data: { country: selectedCountry },
               success: function(response) {
                   $('#cityDropdown').empty(); // Clear existing options
                   $.each(response, function(index, city) {
                       $('#cityDropdown').append($('<option>').text(city).attr('value', city));
                   });
               },
               error: function(xhr, status, error) {
                   console.error('Error:', error);
               }
           });
       });
   });
   </script>

4. Create Controller Action: In your ASP.NET MVC application, create a controller action to handle the AJAX request and return cities based on the selected country:

   public class YourController : Controller
   {
       public IActionResult GetCities(string country)
       {
           // Implement logic to fetch cities based on the selected country
           List<string> cities = GetCitiesByCountry(country); // Dummy function, replace with your logic
           return Json(cities);
       }
   
       // Dummy function to return cities based on country (replace with actual logic)
       private List<string> GetCitiesByCountry(string country)
       {
           // Your logic to fetch cities based on country goes here
           // This is just a placeholder, replace it with actual data retrieval logic
           List<string> cities = new List<string>();
           if (country == "USA")
           {
               cities.Add("New York");
               cities.Add("Los Angeles");
               cities.Add("Chicago");
           }
           else if (country == "UK")
           {
               cities.Add("London");
               cities.Add("Manchester");
               cities.Add("Birmingham");
           }
           // Add more countries and cities as needed
           return cities;
       }
   }