.NET Core第8天_路由端點的切換_注入MVC服務_利用middleware來啟用靜態資源設置預設網址路由

2021 iThome 鐵人賽

DAY 8

自我挑戰組

.NET Core MVC網頁應用開發系列第 8 篇

.NET Core第8天_路由端點的切換_注入MVC服務_利用middleware來啟用靜態資源設置預設網址路由

13th鐵人賽

Samuel

2021-09-08 09:20:59

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當新增好一個.net5的 web空專案後

預設進入點位於Program.cs當中的Main() method
C#程式呼叫了CreateHostBuilder() 建立虛擬主機後
在當中call ConfigureWebHostDefaults() 將web server 指地為Kestrel Server
(.net core預設跨平台server)
並指定啟動的類別為Startup

在此篇有做更深入的探討
.NET Core第3天_使用CLI來創建.NET Core專案_專案架構解析

using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace prjNet5_2
{
    public class Program
    {
        public static void Main(string[] args)
        {
            CreateHostBuilder(args).Build().Run();
        }

        public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .ConfigureWebHostDefaults(webBuilder =>
                {
                    webBuilder.UseStartup<Startup>();
                });
    }
}

可以來測試位於Startup.cs的Configure方法
路由端點改變

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace prjNet5_2
{
    public class Startup
    {
        // This method gets called by the runtime. Use this method to add services to the container.
        // For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940
        public void ConfigureServices(IServiceCollection services)
        {
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            app.UseRouting();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapGet("/First", async context =>
                {
                    await context.Response.WriteAsync("First asp.net core app");
                });
                endpoints.MapGet("/", async context =>
                {
                    await context.Response.WriteAsync("Hello World!");
                });
            });
        }
    }
}

於Startup.cs
當中的ConfigureServices 方法
我們來注入要使用的MVC服務

public void ConfigureServices(IServiceCollection services)
{
        services.AddMvc();
}

在Configure 方法
利用middleware來啟用靜態資源
以及預設網址路由

// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    if (env.IsDevelopment())
    {
        app.UseDeveloperExceptionPage();
    }

    app.UseStaticFiles();//啟用靜態資源可存取性
    app.UseRouting();

    app.UseEndpoints(endpoints =>
    {
        endpoints.MapControllerRoute(
            name: "default",
            pattern: "{Controller=Home}/{Action=Index}/{id?}"
        );//設置MVC默認路由

        //endpoints.MapGet("/", async context =>
        //{
        //    await context.Response.WriteAsync("Hello World!");
        //});
    });
}

透過MapControllerRoute協助我們設定mvc 路由格式
Controller跟Action還有選擇性的id

建立控制器預設要放置於名為Controllers的目錄
創建名為Home的Controller

在新生成的Controller的Index Action方法中
加上透過ViewBag傳遞至View顯示的現在時間

using Microsoft.AspNetCore.Mvc;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace prjNet5_2.Controllers
{
    public class HomeController : Controller
    {
        public IActionResult Index()
        {
            ViewBag.DisplayCurTime = DateTime.Now.ToString();
            return View();
        }
    }
}

新增檢視(跟以前的.net mvc一樣直接對Action右鍵新增Razor檢視)