Optional query string parameters in ASP.NET Razor pages - asp.net-core

Question

In my advanced search form I have around 25 fields. When I submit the form all parameters are passed to the URL even when null. How may I pass the parameters which have only been changed by the user and have a value? All 25 fields are optional.
I have around 25 of these:
[BindProperty(SupportsGet = true)]
[Display(Name = "Foo")]
public int? Foo{ get; set; }
OnGetAsync:
public async Task<IActionResult> OnGetAsync()
{
Properties = await _DarkMatterRepo.FindAsync(Foo, ...)
return Page();
}

Answer 1

How may I pass the parameters which have only been changed by the user and have a value?
To achieve the above the requirement, you can try to check form data and navigate to expected page, like below.
Code of form
<form method="get">
<input type="text" name="name">
<input type="email" name="emailaddress">
<input type="number" name="age">
#*other input fields*#
<input type="submit">
</form>
Dynamically generate QueryString and navigate to specific page
<script>
$( "form" ).on( "submit", function( event ) {
event.preventDefault();
//console.log($(this).serializeArray());
var formdata = $(this).serializeArray();
var parm = "";
$.each(formdata, function (index, item) {
if (item.value!="") {
parm += item.name + "=" + item.value + "&";
}
});
//console.log(parm.substring(0, parm.length - 1));
window.location.href = "#Url.Page("Index")" + "?" + parm.substring(0, parm.length - 1);
});
</script>