public IActionResult NameofAction() { return View(); }这个方法返回一个IActionResult并且方法的名称为NameofAction, action 方法的返回类型可以是像C#函数中的任何类型,IActionResult,ActionResult,JsonResult,string,StatusCodeResult是常用的类型,IActionResult VS ActionResult - IActionResult 是一个接口 ,ActionResult是一个抽象类继承自IActionResult接口,在WebAPI中你将使用ActionResult返回客户端响应。
using AspNetCore.Action.Models; using Microsoft.AspNetCore.Mvc; namespace AspNetCore.Action.Controllers { public class EmployeeController : Controller { // 堆代码 duidaima.com public IActionResult Index() { return View(); } [HttpPost] public IActionResult Index(int id, string name) { string welcomeMessage = $"Welcome Employee: {name} with id: {id}"; return View((object)welcomeMessage); } } }Action方法返回IActionResult类型,调用View()方法返回一个字符串到View,注意我们如果将string类型传递到View,需要将它转换成object类型- View((object)string)。在Views->Employee文件夹下添加Index.cshtml视图,Index试图的代码如下:
@model string; <h2>填充并且提交表单</h2> @{ if (Model != null) { <h3 class="p-3 mb-2 bg-success text-white">@Model</h3> } } <form class="form-horizontal" method="post"> <div class="mb-3 row"> <label class="col-sm-1 control-label">编号</label> <div class="col-sm-11"> <input class="form-control" name="id" /> </div> </div> <div class="mb-3 row"> <label class="col-sm-1 control-label">姓名</label> <div class="col-sm-11"> <input class="form-control" name="name" /> </div> </div> <div class="mb-3 row"> <div class="col-sm-11 offset-sm-1"> <button type="submit" class="btn btn-primary">提交</button> </div> </div> </form>这里有几个值得注意的点:
namespace AspNetCore.Action.Models { public class Employee { public int Id { get; set; } public string Name { get; set; } public int Salary { get; set; } public string Designation { get; set; } public string Address { get; set; } } }现在将类返回给视图,在EmployeeController中添加一个新的action方法Detail
[HttpGet] public IActionResult Detail() { return View(); } [HttpPost] public IActionResult Detail(int id, string name) { var employee=new Employee(); employee.Id = id; employee.Name = name; employee.Salary = 1000; employee.Designation = "Manager"; employee.Address = "New York"; return View(employee); }HttpGet 版本的 Detail方法不会向视图返回任何内容,HttpPost版本的Detail方法中给客户返回一个Employee对象,最后我们将该对象返回给视图。接下来在Views->Employee文件夹中创建Detail.cshtml的Razor视图,注意这次我们在视图的顶端定义了一个Employee类型-@model Employee。
@model Employee; <h2>填充并且提交表单</h2> @{ if (Model != null) { <h3 class="p-3 mb-2 bg-success text-white"> 员工详细信息:@Model.Id,@Model.Name,@Model.Salary,@Model.Designation,@Model.Address </h3> } } <form class="form-horizontal" method="post"> <div class="mb-3 row"> <label class="col-sm-1 control-label">编号</label> <div class="col-sm-11"> <input class="form-control" name="id" /> </div> </div> <div class="mb-3 row"> <label class="col-sm-1 control-label">姓名</label> <div class="col-sm-11"> <input class="form-control" name="name" /> </div> </div> <div class="mb-3 row"> <div class="col-sm-11 offset-sm-1"> <button type="submit" class="btn btn-primary">提交</button> </div> </div> </form>接下来我们将Employee对象的值显示在页面上,运行应用程序并填充表单,提交表单你将会看到employee所有的值,如下图所示:
方法 |
描述 |
View() |
使用默认视图来渲染,例如:如果一个action方法是List并且你使用了没有参数View()方法,List.cshtml视图被呈现 |
View("name_of_view") |
这个版本在参数中传递一个视图名称并且呈现该视图,例如如果你使用View("Show"),然而你Show.cshtml视图将被呈现 |
View(model) |
这个版本给默认视图提提供model数据,这个通常被使用在View中呈现强类型 |
View("name_of_view",model) |
指定一个视图的名称并且给指定的视图提供model数据 |
using Microsoft.AspNetCore.Mvc; namespace AspNetCore.Action.Controllers { public class ExampleController : Controller { public IActionResult Index() { return View(); } public IActionResult ViewBagExample() { ViewBag.CurrentDateTime = DateTime.Now; ViewBag.CurrentYear = DateTime.Now.Year; return View(); } } }我们需要注意如下几点:
public IActionResult TempDataExample() { TempData["CurrentDateTime"] = DateTime.Now; TempData["CurrentYear"] = DateTime.Now.Year; return RedirectToAction("TempDataShow"); } public IActionResult TempDataShow() { return View(); }TempDataExample方法给TempData添加当前时间和当年年份
<h2> Current DateTime & Year: @TempData["CurrentDateTime"] and @TempData["CurrentYear"] </h2>TempData按照字典的方式存储值,通过键值对的方式访问,运行程序,https://localhost:7019/Example/TempDataExample,显示当前时间和年份
public IActionResult SessionExample() { HttpContext.Session.SetString("CurrentDateTime", DateTime.Now.ToString()); HttpContext.Session.SetInt32("CurrentYear", DateTime.Now.Year); return View(); }SetString()方法将添加任何类型作为字符创存储在Session变量中,类似的SetInt32()方法将添加Int值,我们将当前时间和当前年份添加到Session中
@inject Microsoft.AspNetCore.Http.IHttpContextAccessor HttpContextAccessor <h2> Current DateTime & Year: @HttpContextAccessor.HttpContext.Session.GetString("CurrentDateTime"), @HttpContextAccessor.HttpContext.Session.GetInt32("CurrentYear") </h2>我们使用依赖注入指令将服务注入到视图中,我们使用该服务能够访问我们Session中存储的值
@HttpContextAccessor.HttpContext.Session.GetString("CurrentDateTime"), @HttpContextAccessor.HttpContext.Session.GetInt32("CurrentYear")在Session中可以存储复杂类型的变量,例如类,你必须把类序列化成JSON,然后获取该值是再反序列化,我们添加一个新的类:
using System.Text.Json; namespace AspNetCore.Action.Models { public static class SessionExtensions { public static void Set<T>(this ISession session, string key, T value) { session.SetString(key, JsonSerializer.Serialize(value)); } public static T? Get<T>(this ISession session, string key) { var value = session.GetString(key); return value == null ? default : JsonSerializer.Deserialize<T>(value); } } }现在在action方法序列化一个类对象,并且将该对象存储到session中,我们使用刚才类里面定义的序列化方法
HttpContext.Session.Set<Employee>("Employee", new Employee { Name = "KK", Address= "Tokyo" });在视图中我们将json反序列成对象
@{ var employee = HttpContextAccessor.HttpContext.Session.Get<Employee>("Employee"); <p>@employee.Name, @employee.Address</p> }我们可以在services.AddSession()方法中设置cookie的名字和过期时间,具体代码如下:
builder.Services.AddSession(sessionOption => { sessionOption.Cookie.Name = ".myapp"; sessionOption.IdleTimeout= TimeSpan.FromSeconds(10); });四. Action方法的调转方式
public RedirectResult RedirectAction() { return Redirect("/List/Search"); }RedirectPermanent
public RedirectResult RedirectPermanentAction() { return RedirectPermanent("/List/Search"); }RedirectToRoute
public RedirectToRouteResult Redirect() { return RedirectToRoute(new { controller = "Admin", action = "Users", ID = 10 }); }RedirectToRoutePermanent
public RedirectToRouteResult RedirectPermanent() { return RedirectToRoutePermanent(new { controller = "Admin", action = "Users", ID = 10 }); }RedirectToAction
public IActionResult Index() { return RedirectToAction("Privacy"); }
我们将Index方法调转到相同控制器下的Privacy方法,在这种情况下调转的地址为 -/Home/Privacy,如何调用相同控制器下的action?使用RedirectToAction方法单个参数的重载,这个参数提供了相同控制器下的action方法的名称。如何调用不同控制器下的action方法?你也可以使用RedirectToAction方法2个参数的重载,第一个参数指定控制器的名称,第二个参数指定了控制器中action方法的名称。
public RedirectToActionResult Index() { return RedirectToAction("Customer", "List"); }这种情况下调转的url是/Customer/List 。
public IActionResult Index() { //return RedirectToAction("Privacy"); return RedirectToActionPermanent("Privacy"); }五.Action方法返回不同类型的Content
public JsonResult ReturnJson() { return Json(new[] { "Brahma", "Vishnu", "Mahesh" }); }在Views->Example文件夹下创建一个ReturnJson.cshtml的视图并显示JSON文件。
public StatusCodeResult ReturnBadRequest() { return StatusCode(StatusCodes.Status400BadRequest); }例子:返回Unauthorized-401 Status Code
public StatusCodeResult ReturnUnauthorized() { return StatusCode(StatusCodes.Status401Unauthorized); }例子:返回NotFound -404 Status Code
public StatusCodeResult ReturnNotFound() { return StatusCode(StatusCodes.Status404NotFound); }总结