MVC.NET old data comes back after refresh of screen - asp.net-mvc

Question

I have created jquery ajax call in my view page and this successfully posts data.
However, if I press ctrl+F5 to force browser refresh, old data comes back.
If I close down browser and revisit the site, it now shows updated data.
Following is my action in controller.
I am fairly new to MVC.NET and I am sure there is something I am missing.
Can you please advise?
I truly appreciate in advance.
[HttpPost]
[ActionName("EditCategory")]
public ActionResult EditCategory(miniCateObj[] items)
{
int id = int.Parse(items[0].id.Replace("'",""));
string newName = items[0].cateName.Replace("'", "");
ModelState.Remove("CategoryName");
ModelState.Clear();
Category model = _categoryService.GetCategoryByCategoryId( id);
model.CategoryName = newName;
_categoryService.UpdateCategorySite(model);
return View(model);
}
And following is the ajax call I'm using
$.ajax({
type: "POST",
url: '#Url.Action("EditCategory", "CloSite")',
contentType: "application/json; charset=utf-8",
data: JSON.stringify({
"items": [{
"id": "'" + id + "'",
"cateName": "'" + obj.val() + "'"
}]
}),
dataType: "application/xml-urlencode",
success: function () {
alert('Success');
},
error: function (xhr, textStatus, error) {
console.log(xhr.statusText);
console.log(textStatus);
console.log(error);
}
});
Also, I'm not using ORM / Entity Framework. I had problem the projects .savechanges() not updating(in Entity Framework), so I ended up writing direct SQL to update as following,
public int UpdateByCategoryId(int categoryId, string cateName) {
using(var connection = this.Context.Database.Connection) {
if (string.IsNullOrEmpty(connection.ConnectionString)) connection.ConnectionString = ConfigurationHelper.ConnectionString;
var query = string.Format(#"UPDATE Categories set CategoryName = '{0}' where Id = {1}", cateName, categoryId);
return connection.Execute(query);
}
}