Dot.NET Core Routing and Controller Processing discrepancy - asp.net-core

Question

I am trying to use the asp-route- to build a query string that I am using to query the database.
I am confused on how the asp-route- works because I do not know how to specifically use the route that I created in my cshtml page. For example:
If I use the old school href parameter approach, I can then, inside my controller, use the specified Query to get the parameter and query my database, like this:
If I use this href:
#ulsin.custName
then, in the controller, I can use this:
HttpContext.Request.Query["ID"]
The above approach works and I am able to work with the parameter. However, if I use the htmlHelper approach, such as:
<a asp-controller="Report" asp-action="Client" asp-route-id="#ulsin.ID">#ulsin.custName</a>
How do I get that ID from the Controller? The href approach does not seem to work in this case.

Answer 1

According to the Anchor Tag Helper documentation, if the requested route parameter (id in your case) is not found in the route, it is added as a query parameter. Therefore, the following final link will be generated: /Report/Client?id=something. Notice that the query parameter is lowercase.
When you now try to access it in the controller as HttpContext.Request.Query["ID"], since HttpContext.Request.Query is a collection, indexing it would be case-sensitive, and so "ID" will not get you the query parameter "id". Instead of trying to resolve this manually, you can use a feature of the framework known as model binding, which will allow you to automatically and case-insensitively get the value of a query parameter.
Here is an example controller action that uses model binding to get the value of the query parameter id:
// When you add the id parameter, the framework's model binding feature will automatically populate it with the value of the query parameter 'id'.
// You can then use this parameter inside the method.
public IActionResult Client(int id)