How handle event like click in RazorPages by C# functions - asp.net-core

Question

I want to call a C# function when I click on a button, or select an item in selectList on the razor page.
In blazor , it is possible like this code:
<button class="btn btn-info form-control" #onclick="AddNewCategory" >Add New Category</button>
but in razor page, I can't use it
Please help me!

Answer 1

If you want to select an item in selectList on the razor page when clicking on a button,you can try to use js,here is a demo.When clicking the button,the selected value will be 4.
<select id="select1">
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="4">4</option>
</select>
<button onclick="changeSelectedItem()">test</button>
#section Scripts{
<script>
function changeSelectedItem() {
$("#select1").val(4);
}
</script>
}
And if you want to call a C# function when I click on a button,you can use ajax to call a handler.here is a demo:
cshtml:
#Html.AntiForgeryToken()
<button onclick="callHandler()">callHandler</button>
#section Scripts{
<script>
function callHandler() {
$.ajax({
type: "POST",
url: "?handler=TestHandler",
headers: { "RequestVerificationToken": $('input[name="__RequestVerificationToken"]').val() },
success: function (data) {
//...
}
});
}
</script>
}
cshtml.cs:
public void OnPostTestHandler()
{
//do something here
}