asp .net. MVC 增删改查

ASP.NET MVC 是一种基于模型-视图-控制器 (MVC) 架构的 Web 应用程序框架。它提供了一种创建 Web 应用程序的模式，可以使开发人员将应用程序的逻辑、布局和用户界面分开。

在 ASP.NET MVC 中，常见的增删改查操作可以使用以下步骤完成：

1. 创建模型类：定义要操作的实体类。

2. 创建控制器类：定义处理请求和响应的代码，包括数据操作和视图渲染。

3. 创建视图：定义呈现数据的 HTML 界面。

4. 实现数据操作：可以使用 Entity Framework 或者其他 ORM 框架来实现数据库的增删改查操作。

下面是一个简单的示例，演示如何在 ASP.NET MVC 中实现增删改查操作：

1. 创建模型类：

public class Book
{
    public int BookId { get; set; }
    public string Title { get; set; }
    public string Author { get; set; }
    public decimal Price { get; set; }
}

2. 创建控制器类：

public class BookController : Controller
{
    // 显示书籍列表
    public ActionResult Index()
    {
        var books = db.Books.ToList();
        return View(books);
    }

    // 添加书籍
    public ActionResult Add()
    {
        return View();
    }

    [HttpPost]
    public ActionResult Add(Book book)
    {
        db.Books.Add(book);
        db.SaveChanges();
        return RedirectToAction("Index");
    }

    // 修改书籍
    public ActionResult Edit(int id)
    {
        var book = db.Books.Find(id);
        return View(book);
    }

    [HttpPost]
    public ActionResult Edit(Book book)
    {
        db.Entry(book).State = EntityState.Modified;
        db.SaveChanges();
        return RedirectToAction("Index");
    }

    // 删除书籍
    public ActionResult Delete(int id)
    {
        var book = db.Books.Find(id);
        db.Books.Remove(book);
        db.SaveChanges();
        return RedirectToAction("Index");
    }

    private ApplicationDbContext db = new ApplicationDbContext();
}

3. 创建视图：

@model IEnumerable<Book>

<h2>书籍列表</h2>

<p>
    @Html.ActionLink("添加书籍", "Add")
</p>

<table class="table">
    <tr>
        <th>
            @Html.DisplayNameFor(model => model.Title)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.Author)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.Price)
        </th>
        <th></th>
    </tr>

    @foreach (var item in Model) {
        <tr>
            <td>
                @Html.DisplayFor(modelItem => item.Title)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.Author)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.Price)
            </td>
            <td>
                @Html.ActionLink("编辑", "Edit", new { id=item.BookId }) |
                @Html.ActionLink("删除", "Delete", new { id=item.BookId })
            </td>
        </tr>
    }

</table>

@model Book

<h2>添加书籍</h2>

@using (Html.BeginForm()) 
{
    @Html.AntiForgeryToken()

    <div class="form-group">
        @Html.LabelFor(model => model.Title, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.EditorFor(model => model.Title, new { htmlAttributes = new { @class = "form-control" } })
            @Html.ValidationMessageFor(model => model.Title, "", new { @class = "text-danger" })
        </div>
    </div>

    <div class="form-group">
        @Html.LabelFor(model => model.Author, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.EditorFor(model => model.Author, new { htmlAttributes = new { @class = "form-control" } })
            @Html.ValidationMessageFor(model => model.Author, "", new { @class = "text-danger" })
        </div>
    </div>

    <div class="form-group">
        @Html.LabelFor(model => model.Price, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.EditorFor(model => model.Price, new { htmlAttributes = new { @class = "form-control" } })
            @Html.ValidationMessageFor(model => model.Price, "", new { @class = "text-danger" })
        </div>
    </div>

    <div class="form-group">
        <div class="col-md-offset-2 col-md-10">
            <input type="submit" value="添加" class="btn btn-default" />
        </div>
    </div>
}

<div>
    @Html.ActionLink("返回列表", "Index")
</div>

@model Book

<h2>编辑书籍</h2>

@using (Html.BeginForm()) 
{
    @Html.AntiForgeryToken()

    <div class="form-group">
        @Html.LabelFor(model => model.Title, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.EditorFor(model => model.Title, new { htmlAttributes = new { @class = "form-control" } })
            @Html.ValidationMessageFor(model => model.Title, "", new { @class = "text-danger" })
        </div>
    </div>

    <div class="form-group">
        @Html.LabelFor(model => model.Author, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.EditorFor(model => model.Author, new { htmlAttributes = new { @class = "form-control" } })
            @Html.ValidationMessageFor(model => model.Author, "", new { @class = "text-danger" })
        </div>
    </div>

    <div class="form-group">
        @Html.LabelFor(model => model.Price, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.EditorFor(model => model.Price, new { htmlAttributes = new { @class = "form-control" } })
            @Html.ValidationMessageFor(model => model.Price, "", new { @class = "text-danger" })
        </div>
    </div>

    <div class="form-group">
        <div class="col-md-offset-2 col-md-10">
            <input type="submit" value="保存" class="btn btn-default" />
        </div>
    </div>
}

<div>
    @Html.ActionLink("返回列表", "Index")
</div>

4. 实现数据操作：

可以使用 Entity Framework 来实现数据库的增删改查操作，具体代码可以参考以下示例：

public class ApplicationDbContext : DbContext
{
    public DbSet<Book> Books { get; set; }
}

注意，在使用 Entity Framework 之前，还需要进行一些配置，例如在 Web.config 中添加连接字符串。