Hi rani,
Check this example. Now please take its reference and correct your code.
For autocomplete i have refered below article.
Database
For this example I have used of Northwind database that you can download using the link given below.
Download Northwind Database
Model
public class CustomerModel
{
    public string Id { get; set; }
    public string Name { get; set; }
    public string City { get; set; }
    public string Country { get; set; }
}
Namespaces
using System.Collections.Generic;
using System.Configuration;
using System.Data.SqlClient;
using System.Linq;
Controller
public class HomeController : Controller
{
    // GET: /Home/
    public ActionResult Index()
    {
        return View();
    }
    [HttpPost]
    public JsonResult GetCountries()
    {
        string query = "SELECT CustomerID,ContactName,City,Country FROM Customers";
        SqlCommand cmd = new SqlCommand(query);
        var countries = GetCustomers(query, cmd).Select(x => new { Country = x.Country }).Distinct().ToList();
        return Json(countries, JsonRequestBehavior.AllowGet);
    }
    private static List<CustomerModel> GetCustomers(string query, SqlCommand cmd)
    {
        List<CustomerModel> customers = new List<CustomerModel>();
        string conString = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
        using (SqlConnection con = new SqlConnection(conString))
        {
            cmd.Connection = con;
            con.Open();
            using (SqlDataReader sdr = cmd.ExecuteReader())
            {
                while (sdr.Read())
                {
                    customers.Add(new CustomerModel
                    {
                        Id = sdr["CustomerID"].ToString(),
                        Name = sdr["ContactName"].ToString(),
                        City = sdr["City"].ToString(),
                        Country = sdr["Country"].ToString()
                    });
                }
            }
            con.Close();
        }
        return customers;
    }
}
View
<body ng-app="MyApp" ng-controller="MyController">
    <div angucomplete-alt id="txtCountries" placeholder="Country" pause="100" selected-object="Search"
        focus-out="Validate()" local-data="Countries" search-fields="Country" title-field="Country"
        minlength="1" input-class="form-control" match-class="highlight">
    </div>
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.7/css/bootstrap.min.css" />
    <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.5.5/angular.js"></script>
    <script type="text/javascript" src="../../AnguAutoComplete/angucomplete-alt.js"></script>
    <link type="text/css" rel="stylesheet" href="../../AnguAutoComplete/angucomplete-alt.css" />
    <script type="text/javascript">
        var app = angular.module('MyApp', ['angucomplete-alt']);
        app.controller('MyController', function ($scope, $http, $window) {
            $scope.Countries = null;
            $http({
                method: 'POST',
                url: '/Home/GetCountries/'
            }).success(function (data) {
                if (data.length > 0) {
                    $scope.Countries = data;
                }
            });
            $scope.Validate = function (text) {
                if (text == undefined) {
                    $window.alert("Option must be selected from the list only.");
                    return true;
                }
            }
            $scope.Search = function (selected) {
                $window.alert(selected.title);
            }
        });
    </script>
</body>
Screenshot
