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Passing Parameters Using the Route Value

Passing Parameters Using the Route Value

Learn about implementing parameter passing in ASP.NET Core using the action method, showcasing a concise test for retrieving product details via a web browser.

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We’ll learn to pass parameters in ASP.NET Core. We’ll add an action method to the controller and create a corresponding view to display the output. Let’s dive into it.

Passing parameter

One way to pass a simple parameter is to use the id segment defined in the default route:

Step 1: In HomeController.cs, add an action method named ProductDetail, as shown in the following code:

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public IActionResult ProductDetail(int? id)
{
  if (!id.HasValue)
  {
    return BadRequest("You must pass a product ID in the route, for example, / Home / ProductDetail / 21");
  }
  Product? model = db.Products.SingleOrDefault(p => p.ProductId == id);
  if (model is null)
  {
    return NotFound($"ProductId {id} not found.");
  }
  return View(model); // pass model to view and then return result
}
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