新增文章已經做完了，今天就來做撈出文章列表的功能，這樣才能看到新增的成果。
我們今天會把查詢文章做在，一進去的首頁，所以放在HomeController 裡面，因為正常來說一進到首頁就看到文章是合理的。

目標：
1.查詢文章介面、實做
2.HomeController 注入Article 介面
3.做View 頁面

步驟：

step1.IArticleService.cs

Task<IList<Article>> GetArticle(long? id);

step2.ArticleService.cs

public async Task<IList<Article>> GetArticle(long? id)
        {
            if (id == null)
            {
                return await _db.Articles
                .Where(x => x.IsDelete == false)
                .OrderByDescending(x => x.Id)
                .Take(1)
                .ToListAsync();
            }
            else
            {
                return await _db.Articles
                .Where(x => x.IsDelete == false && x.Id == id)
                .OrderByDescending(x => x.Id)
                .ToListAsync();
            }
        }

step3. HomeController 改寫成這樣 (這邊很單純，就是取值出來後往View送)

public async Task<IActionResult> Index()
        {
            var model = await _article.GetArticle(null);
            var result = new List<ArticleViewModel>();

            if (model is not null && model.Count > 0)
            {
                result = model.Select(x => new ArticleViewModel
                {
                    Id = x.Id,
                    ArticleContent = x.ArticleContent,
                    Title = x.Title
                }).ToList();

                TempData["ArticleLastId"] = result.Last().Id.ToString();
            }

            return View(result);
        }

step4. 在 Viewmodel 資料夾裡面新增此物件(用來傳直到View 裡面的物件)

public class ArticleViewModel
    {
        public long Id { get; set; }

        public string Title { get; set; } = string.Empty;

        public string ArticleContent { get; set; } = string.Empty;
    }

step5. 新增首頁畫面

@model IEnumerable<ArticleViewModel>;

@{
    ViewData["Title"] = "Home Page";
}

<div class="text-center mb-2">
    <h1 class="display-4">Welcome</h1>
</div>
<hr/>
@if (Model != null && Model.Count() > 0)
{
    <div id="articleIndex" class="text-center mt-5">
        @foreach (var item in Model)
        {
            <h3 class="display-4">
                <a href="~/Article/@item.Id">@item.Title</a>
            </h3>
        }
    </div>
}

這樣成功執行起來的話，應該就可以看到首頁有資料囉~