How can I get full info on update page - asp.net-core-mvc

Question

I have an ASP.NET Core MVC project without Entity Framework.
When I click on the "update" button, I want to update page and make it does not become empty.
This is my view:
<div class="form-group">
<form asp-action="OdemeTurGuncelle">
<div asp-validation-summary="ModelOnly" class="text-danger"></div>
<div class="form-group">
ID
<input asp-for="odemetur_id" class="form-control" />
<span asp-validation-for="odemetur_id" class="text-danger"></span>
</div>
<div class="form-group">
Ödeme Türü
<input asp-for="odemetur_adi" class="form-control" />
<span asp-validation-for="odemetur_adi" class="text-danger"></span>
</div>
<div class="form-group">
<input type="submit" value="Save" class="btn btn-primary" />
</div>
</form>
</div>
And my controller :
[HttpGet]
public IActionResult OdemeTurGuncelle()
{
return View();
}
[HttpPost]
public IActionResult OdemeTurGuncelle(OdemeTur odemeTur)
{
string constr = Genel.conString;
using (NpgsqlConnection con = new NpgsqlConnection(constr))
{
string query = "UPDATE odemeturleri SET odemetur_adi=#odemetur_adi WHERE odemetur_id=#odemetur_id";
using (NpgsqlCommand cmd = new NpgsqlCommand(query))
{
cmd.Connection = con;
con.Open();
cmd.Parameters.AddWithValue("#odemetur_id", odemeTur.odemetur_id);
cmd.Parameters.AddWithValue("#odemetur_adi", odemeTur.odemetur_adi);
cmd.ExecuteNonQuery();
con.Close();
}
}
// return View(ders);
return RedirectToAction("Index");
}
I can do it with Entity Framework, but I want to do it without EF