canvasManagement/Management.Web/Shared/Components/AssignmentForm/RubricEditor.razor

@using Management.Web.Shared.Components

@inject CoursePlanner planner
@inject AssignmentEditorContext assignmentContext

@code
{
  private IEnumerable<RubricItem> rubric { get; set; } = Array.Empty<RubricItem>();

  protected override void OnInitialized()
  {
    assignmentContext.StateHasChanged += reload;
    reload();
  }
  private void reload()
  {
    if (assignmentContext.Assignment != null)
    {
      rubric = assignmentContext.Assignment.Rubric;
    }
    this.InvokeAsync(this.StateHasChanged);
  }
  public void Dispose()
  {
    assignmentContext.StateHasChanged -= reload;
  }

  private void save()
  {
    if (assignmentContext.Assignment != null)
    {
      var totalRubricPoints = rubric
        .Where(r => !r.Label.Contains(RubricItem.extraCredit))
        .Select(s => s.Points)
        .Sum();
      var newAssignment = assignmentContext.Assignment with
        {
          Rubric = rubric,
          PointsPossible = totalRubricPoints,
        };
      assignmentContext.SaveAssignment(newAssignment);
      StateHasChanged();
    }
  }
  private void addItem()
  {
    if (assignmentContext.Assignment != null)
    {
      rubric = rubric.Append(new RubricItem
      {
        Id = Guid.NewGuid().ToString(),
        Label = "",
        Points = 0
      });
    }
  }
  private void removeItem()
  {
    if (assignmentContext.Assignment != null)
    {
      rubric = rubric.Take(rubric.Count() - 1);
      save();
    }
  }
  private void editItem(RubricItem newItem)
  {
    if (assignmentContext.Assignment != null)
    {
      rubric = rubric.Select(i => i.Id == newItem.Id ? newItem : i);
      save();
    }
  }
  private void MoveUp(RubricItem item)
  {
    if (assignmentContext.Assignment != null)
    {
      var rubricList = rubric.ToList();
      var index = rubricList.IndexOf(item);

      if (index > 0)
      {
        var previous = rubricList[index - 1];
        rubricList[index - 1] = item;
        rubricList[index] = previous;
        rubric = rubricList;
        save();
      }
    }
  }
  private void MoveDown(RubricItem item)
  {
    if (assignmentContext.Assignment != null)
    {
      var rubricList = rubric.ToList();
      var index = rubricList.IndexOf(item);

      if (index < rubricList.Count())
      {
        var next = rubricList[index + 1];
        rubricList[index + 1] = item;
        rubricList[index] = next;
        rubric = rubricList;
        save();
      }
    }
  }
}

<br>
<h5>Rubric</h5>
<ul class="list-group">
@foreach (var rubricItem in rubric)
  {
    <RubricEditorItem 
      RubricItem="rubricItem" 
      OnUpdate="editItem"
      MoveUp="() => MoveUp(rubricItem)"
      MoveDown="() => MoveDown(rubricItem)"
    />
  }
</ul>

<div class="text-end my-1">
  <button
    @onclick:preventDefault="true"
    @onclick="removeItem"
    type="button"
    class="btn btn-outline-danger"
  >
    - rubric item
  </button>
  <button
    @onclick:preventDefault="true"
    @onclick="addItem"
    type="button"
    class="btn btn-outline-primary"
  >
    + rubric item
  </button>
</div>