My Model:
public class Message
{
    public string text { get; set; }
    public int reloads { get; set; }
}
My Controller:
[HttpPost]
    public IActionResult LoadPage(Message model)
    {
        ++model.reloads;
        return View(model);
    }
    public IActionResult LoadPage()
    {
        return View();
    }
And finally my view:
@if (@Model != null)
{
    <h1>reloads: @Model.reloads</h1>
    <p>@Model.text</p><br />
}
<form asp-action="LoadPage" method="post">
    <input asp-for="text" type="text" />
    <input asp-for="reloads" type="hidden" />
    <input type="submit" />
</form>
I have tried so many different versions of this and it wont increment the reload-int.