public IActionResult getWardsFromVDC(long vdc_id)
{
 try
 {
 List<Ward> wards = wardRepo.getByVdcId(vdc_id).ToList();
 List<Dictionary<string, string>> values = new List<Dictionary<string, string>>();
 foreach (var ward in wards)
 {
 Dictionary<string, string> value = new Dictionary<string, string>();
 value["ward_id"] = ward.ward_id.ToString();
 value["ward_name"] = ward.ward_name;
 values.Add(value);
 }
 Dictionary<string, object> data = new Dictionary<string, object>();
 data["data"] = values;
 var json = JsonConvert.SerializeObject(data);
 return Json(json);
 }
 catch (Exception ex)
 {
 return Json(ex.Message);
 }
}

List wards = wardRepo.getByVdcId(vdc_id).ToList();

Dictionary<string, object> data = new Dictionary<string, object>(); data["data"] = values;

 var json = JsonConvert.SerializeObject(data);

public IActionResult getWardsFromVDC(long vdc_id)
{
 try
 {
 List<Ward> wards = wardRepo.getByVdcId(vdc_id).ToList();
 List<Dictionary<string, string>> values = new List<Dictionary<string, string>>();
 foreach (var ward in wards)
 {
 Dictionary<string, string> value = new Dictionary<string, string>();
 value["ward_id"] = ward.ward_id.ToString();
 value["ward_name"] = ward.ward_name;
 values.Add(value);
 }
 Dictionary<string, object> data = new Dictionary<string, object>();
 data["data"] = values;
 var json = JsonConvert.SerializeObject(data);
 return Json(json);
 }
 catch (Exception ex)
 {
 return Json(ex.Message);
 }
}

List<Ward> wards = wardRepo.getByVdcId(vdc_id).ToList();

 Dictionary<string, object> data = new Dictionary<string, object>();
 data["data"] = values;
 var json = JsonConvert.SerializeObject(data);

List wards = wardRepo.getByVdcId(vdc_id).ToList();

is getting list of Ward class from database. Then a loop is used to put all the values in List of Dictionaries .

Dictionary<string, object> data = new Dictionary<string, object>(); data["data"] = values;

 var json = JsonConvert.SerializeObject(data);

is putting all those values in "data" key in another dictionary and then value is serialized and returned as JSON