Are there any Pitfalls to this approach which I am not seeing

问题

Service Registration

  services.AddScoped(typeof(PageStorageService<>), typeof(PageStorageService<>));

Service Declaration

 public interface IStoredPage<T>
    {   
        T PageState { get; set; }
    }
    public class PageStorageService<T> : IStoredPage<T>
    {
        public T PageState { get; set; }
    }

Usage in CounterPage

@page "/counter"

@using BlazorApp1.Data
 
<h1>Counter</h1>

<p>Current count: @currentCount</p>

@inject PageStorageService<Counter> StorageService

<button class="btn btn-primary" @onclick="IncrementCount">Click me</button>

@code {

    private int currentCount = 0;

    private void IncrementCount()
    {
        currentCount++;
    }

    protected override async Task OnParametersSetAsync()
    {
        // reset what we want from stored copy
        if (StorageService.PageState != null)
        {
            currentCount = StorageService.PageState.currentCount;

        }
        //reconnect for this page lifespan we have a reference copy of the pages class
        // which is copied into the service  Or so experimentation seems to indicate
        StorageService.PageState = this;
    }

I have run multiple small tests like the one above)

And this Improvement to use OnInitialziedAsync ( an additional list was added to the counter class that is not shown )

@using BlazorApp1.Data
 
<h1>Counter2</h1>

<p>Current count: @currentCount</p>
<p>PageStateNull : @PageStateNullCount</p>

<div>  @((MarkupString)string.Join("\r\n", TestDataSave))  </div>

    @inject PageStorageService<Counter2> StorageService

    <button class="btn btn-primary" @onclick="IncrementCount">Click me</button>

    @code {

        private int PageStateNullCount = 0;

        private List<string> TestDataSave;

        private int currentCount = 0;

        private void IncrementCount()
        {
            TestDataSave.Add("<div>count before Inc : " + currentCount.ToString() + "</div>");
            currentCount++;
            TestDataSave.Add("<div>count after Inc :" + currentCount.ToString() + "<div>");

        }

        protected override Task OnInitializedAsync()
        {
            // reset what we want from stored copy
            if (StorageService.PageState != null)
            {
                currentCount = StorageService.PageState.currentCount;
                TestDataSave = StorageService.PageState.TestDataSave;
                PageStateNullCount = StorageService.PageState.PageStateNullCount;
            }
            else
            {
                PageStateNullCount++;
                //create for the first time aka read from database
                TestDataSave = new List<string>();
                TestDataSave.Add("<div>OnParametersSetAsync</div>");
            }


            //reconnect 
            StorageService.PageState = this;

            return base.OnInitializedAsync();
        }

This seems pretty clean and straight forward to me. But more eyes are generally better. It follows the same general pattern as the Local storage solutions i have seen (in my case I am only looking to store filters and tab selections for a dashboard type app -- I won't have large forms etc and I am more interested in the advantages of having page state in memory than the occasional server crash . The fact that it is injected as a service means any page that I want to use can opt In.. etc Thoughts, rocks, things I should have thought of?

来源：https://stackoverflow.com/questions/65044349/are-there-any-pitfalls-to-this-approach-which-i-am-not-seeing

标签

generics

dependency-injection

blazor