I'm trying to get a delete operation to work on an entity with a composite key on a Razor page using ASP.NET Core 3.0 and Entity Framework 6. The entity in question is a `CourseAssignment` whose composite key is composed of an `InstructorID` value and a `CourseID` value.

For an entity with an ordinary, single-field key—say, a `Course` entity with a `CourseID` primary key—the code on the razor page is this:

```
<form method="post">
  <input type="hidden" asp-for="Course.CourseID" />
  <input type="submit" value="Delete" class="btn btn-danger" /> |
  <a asp-page="./Index">Back to List</a>
</form>

```

Which produces a URL like this:
<https://localhost:44388/Courses/Delete?id=1045>

The C# code that acts on this is:

```cs
public async Task<IActionResult> OnPostAsync(int? id) {

  if (id == null) {
    return NotFound();
  }

  Course = await _context.Courses.FindAsync(id);

  if (Course != null) {
    _context.Courses.Remove(Course);
    await _context.SaveChangesAsync();
  }

  return RedirectToPage("./Index");

}

```

How do I change both the razor page and the C# `OnPostAsync` action to handle the entity with a composite key requiring two values?

Thanks!