I want to know why request.form is null

i making login system with razor page

I want to get data from cshtml inputbox

request.form is null

i learn razor page this link this

I want to know why request.form is null

this is cshtml

@page   "/Login"
@model WebApplication1.Pages.Login.LoginPageModel
@addTagHelper *, Microsoft.AspNetCore.Mvc.TagHelpers

@{
    Layout = null;
}




<form class="form-horizontal" method="post">
    <div class="form-group">
        <label for="Userid" class="col-sm-2 control-label">Userid</label>
        <div class="col-md-4">
            <input type="text" class="form-control" name="Userid">
        </div>
    </div>
    <div class="form-group">
        <label for="Userpassword" class="col-sm-2 control-label">Userpassword</label>
        <div class="col-md-4">
            <input type="password" class="form-control" name="Userpassword">
        </div>
    </div>
</form>

<form method="post">
    <input asp-page-handler="Login" class="btn" type="submit" value="login" />
</form>

this is cs

   public IActionResult OnPostLogin()
        {
            string _id = Request.Form["Userid"].ToString();
            string _password = Request.Form["Userpassword"].ToString();

            if (_id.Length == 0)
                return Page();
            
        }

doesnot pass _id.Length == 0