Asp.net Core 入门实战

Asp.Net Core 是开源,跨平台,模块化,快速而简单的Web框架.

Asp.net Core官网的一个源码合集,方便一次性Clone

目录

持续更新,也可以通过我的网站访问,欢迎探讨交流

快速入门

安装

下载安装 .NET SDK

查看dotnet sdk 版本

$ dotnet --version`
2.1.4

创建项目目录

$ mkdir study
$ cd study

使用 dotnet new 命令创建项目

$ dotnet new console -n Demo
$ cd Demo

在 VS Code中打开Demo文件夹

一个最小的应用

打开 Program.cs

using System;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http; namespace Demo
{
class Program
{
static void Main(string[] args)
{
var host = new WebHostBuilder()
.UseKestrel()
.UseStartup<Startup>()
.Build();
host.Run();
}
} class Startup
{
public void Configure(IApplicationBuilder app)
{
app.Run(async context =>
{
await context.Response.WriteAsync("Hello, World!");
});
}
}
}

安装相关的Nuget包

$ dotnet add package Microsoft.AspNetCore.Hosting --version 2.0.1
$ dotnet add package Microsoft.AspNetCore.Server.Kestrel --version 2.0.1

下载依赖项

$ dotnet restore

运行

$ dotnet run

输出结果:

Hosting environment: Production
Content root path: C:\netcore\study\Demo\bin\Debug\netcoreapp2.0\
Now listening on: http://localhost:5000
Application started. Press Ctrl+C to shut down.

项目模板

根据指定的模板,创建新的项目、配置文件或解决方案。

$ dotnet new -h
使用情况: new [选项] 选项:
-h, --help 显示有关此命令的帮助。
-l, --list 列出包含指定名称的模板。如果未指定名称,请列出所有模板。
-n, --name 正在创建输出的名称。如果未指定任何名称,将使用当前目录的名 称。
-o, --output 要放置生成的输出的位置。
-i, --install 安装源或模板包。
-u, --uninstall 卸载一个源或模板包。
--type 基于可用的类型筛选模板。预定义的值为 "project"、"item" 或 "other"。
--force 强制生成内容,即使该内容会更改现有文件。
-lang, --language 指定要创建的模板的语言。 模板 短名称 语言 标记
-------------------------------------------------------------------------------- ------------------------
Console Application console [C#], F#, VB Common/Console
Class library classlib [C#], F#, VB Common/Library
Unit Test Project mstest [C#], F#, VB Test/MSTest
xUnit Test Project xunit [C#], F#, VB Test/xUnit
ASP.NET Core Empty web [C#], F# Web/Empty
ASP.NET Core Web App (Model-View-Controller) mvc [C#], F# Web/MVC
ASP.NET Core Web App razor [C#] Web/MVC/Razor Pages
ASP.NET Core with Angular angular [C#] Web/MVC/SPA
ASP.NET Core with React.js react [C#] Web/MVC/SPA
ASP.NET Core with React.js and Redux reactredux [C#] Web/MVC/SPA
ASP.NET Core Web API webapi [C#], F# Web/WebAPI
global.json file globaljson Config
NuGet Config nugetconfig Config
Web Config webconfig Config
Solution File sln Solution
Razor Page page Web/ASP.NET
MVC ViewImports viewimports Web/ASP.NET
MVC ViewStart viewstart Web/ASP.NET Examples:
dotnet new mvc --auth Individual
dotnet new page --namespace
dotnet new --help

使用dotnet new 选择 console 模板 创建项目

$ dotnet new console -n Demo
$ cd Demo

创建后的项目文档结构是

.
├── Demo
│ ├── Demo.csproj
│ └── Program.cs

路由

启用,配置路由

using System;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Routing;
using Microsoft.Extensions.DependencyInjection; namespace Demo { class Startup {
public void ConfigureServices (IServiceCollection services) {
//启用路由
services.AddRouting ();
}
public void Configure (IApplicationBuilder app) {
//配置路由
app.UseRouter (routes => {
//根路由 (/)
routes.MapGet("", context =>
{
return context.Response.WriteAsync("Hello, World!");
});
//在根路由 (/) 上,配置 /hello Get请求的路由
routes.MapGet ("hello", context => {
return context.Response.WriteAsync ("Got a Get request at /hello");
});
});
}
}
}

安装相关的Nuget包

$ dotnet add package Microsoft.AspNetCore.Routing --version 2.0.1

下载依赖项

$ dotnet restore

运行

$ dotnet run

访问 http://localhost:5000/hello ,输出结果:

Got a Get request at /hello

对 /user 路由的 POST 请求进行响应:

routes.MapPost("hello", context => {
return context.Response.WriteAsync ("Got a Post request at /hello");
})

对 /user 路由的 PUT 请求进行响应:

routes.MapPut("hello", context => {
return context.Response.WriteAsync ("Got a Put request at /hello");
})

对 /user 路由的 DELETE 请求进行响应:

routes.MapDelete("hello", context => {
return context.Response.WriteAsync ("Got a Dlete request at /hello");
})

静态文件

启用,配置静态资源

创建 wwwroot文件夹

$ mkdir wwwroot
$ cd wwwroot

复制 index.html 到 wwwroot目录

$ mkdir images
$ cd images

复制 favicon.png 到 images文件夹下

项目结构图如下:
.
├── Demo
│ ├── wwwroot
│ │ ├── images
│ │ │ ├── favicon.png
│ │ ├── index.html
│ ├── Demo.csproj
│ └── Program.cs

更改 Program.cs,设置ContentRoot路径为当前项目根目录,启用静态资源

using System;
using System.IO;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Routing;
using Microsoft.Extensions.DependencyInjection; namespace Demo {
class Program {
static void Main (string[] args) {
Console.WriteLine (AppContext.BaseDirectory);
var host = new WebHostBuilder ()
.UseKestrel ()
//设置 ContentRoot, ContentRoot是任何资源的根路径,比如页面和静态资源
.UseContentRoot(Directory.GetCurrentDirectory())
.UseStartup<Startup>()
.Build ();
host.Run ();
}
} class Startup {
public void Configure (IApplicationBuilder app) {
//使用静态资源,默认的目录是 /wwwroot
app.UseStaticFiles ();
}
}
}

运行

http://localhost:5000/index.html

http://localhost:5000/images/favicon.png

配置其他文件夹

新建文件夹myfiles

$ mkdir myfiles
$ cd myfiles

创建一个新的 index.html到myfiles文件夹,配置并使用myfiles文件夹

app.UseStaticFiles (new StaticFileOptions {
FileProvider = new PhysicalFileProvider (
Path.Combine (Directory.GetCurrentDirectory (), "myfiles")),
RequestPath = "/myfiles"
});

运行

http://localhost:5000/myfiles/index.html

页面渲染

Razor模板引擎

Asp.net Core自带的模板引擎是 Razor模板引擎,传统的Razor页面以cshtml结尾, 阅读Razor语法

遗憾的是Razor模板引擎在Asp.net Core中封装在了MVC模块之中,需要做一些扩展才可以单独拿出来使用

创建模板页面

创建 views文件夹

$ mkdir views
$ cd views

创建 index.cshtml 页面

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
</head>
<body>
<ul>
@for (int i = 0; i < 5; i++)
{
<li>第@(i + 1)行</li>
}
</ul>
</body>
</html>

使用模板

using System;
using System.IO;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Routing;
using Microsoft.Extensions.DependencyInjection; namespace Demo
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine(AppContext.BaseDirectory);
var host = new WebHostBuilder()
.UseKestrel()
.UseContentRoot(Directory.GetCurrentDirectory())
.UseStartup<Startup>()
.Build();
host.Run();
}
} class Startup
{
public void ConfigureServices(IServiceCollection services)
{
//启用Mvc
services.AddMvc(); //扩展类
services.AddSingleton<RazorViewRenderer>(); }
public void Configure(IApplicationBuilder app)
{
app.UseRouter(routes =>
{
//根路径 /
routes.MapGet("", context =>
{
return context.Render("/views/index.cshtml");
}
});
} }
}

安装相关的Nuget包

$ dotnet add package Microsoft.AspNetCore.Mvc --version 2.0.2

下载依赖项

$ dotnet restore

运行

$ dotnet run

结果

第1行
第2行
第3行
第4行
第5行

渲染数据

新增实体类 UserInfo

public class UserInfo
{
public string Name { get; set; }
public int Age { get; set; }
}

新增user.cshtml页面

@using Demo;
@model UserInfo
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
</head>
<body>
<ul>
<li>姓名:@Model.Name</li>
<li>年龄:@Model.Age</li>
</ul>
</body>
</html>

更改Program.cs

app.UseRouter(routes =>
{
//根路径 /
routes.MapGet("", context =>
{
return context.Render("/views/index.cshtml");
}
routes.MapGet("/user", context =>
{
return context.Render("/views/user.cshtml", new UserInfo() { Name = "张三", Age = 18 });
});
});

运行

$ dotnet run

结果

姓名:张三
年龄:18

请求数据

QueryString

var queryCollection = context.Request.Query;
foreach (var item in queryCollection)
{
Console.WriteLine(item.Key + ":" + item.Value);
}

Form

if (context.Request.ContentType.ToLower().Contains("application/x-www-form-urlencoded")
{
var formCollection = context.Request.Form;
foreach (var item in formCollection)
{
Console.WriteLine(item.Key + ":" + item.Value);
}
}

Files

var fileCollections = context.Request.Form.Files;
var rootPath = context.RequestServices.GetService<IHostingEnvironment>().ContentRootPath;
foreach (var item in fileCollections)
{ var path = Path.Combine(rootPath,item.FileNa
using (var stream = new FileStream(path, FileMode.Create))
{
await item.CopyToAsync(stream);
}
Console.WriteLine(item.FileName + ":" + item.Length);
}

Header

var headerCollection = context.Request.Headers;
foreach (var item in headerCollection)
{
Console.WriteLine(item.Key + ":" + item.Value);
}

Body

StreamReader reader = new StreamReader(context.Request.Body);
string text = reader.ReadToEnd();

Cookies

var cookieCollection=context.Request.Cookies;
foreach (var item in cookieCollection)
{
Console.WriteLine(item.Key + ":" + item.Value);
}

错误和重定向

重定向

context.Response.Redirect("path")

状态代码页

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Diagnostics;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Routing;
using Microsoft.Extensions.DependencyInjection;
using System;
using System.IO;
using System.Text.Encodings.Web; namespace Demo
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine(AppContext.BaseDirectory);
var host = new WebHostBuilder()
.UseKestrel()
.UseContentRoot(Directory.GetCurrentDirectory())
.UseStartup<Startup>()
.Build();
host.Run();
}
} class Startup
{
public void ConfigureServices(IServiceCollection services)
{
//启用路由
services.AddRouting();
services.AddMvc();
services.AddSingleton<RazorViewRenderer>(); }
public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
//启用状态码页
app.UseStatusCodePages(); app.UseRouter(routes =>
{
//根路径 /
routes.MapGet("", context =>
{
return context.Render("/views/index.cshtml");
}
});
} }
}

自定义状态码页

新增 404.cshtml

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
</head>
<body>
<h1> Oops! Page Not Found ! </h1>
</body>
</html>

配置和使用自定义的状态码页

app.UseStatusCodePagesWithRedirects("/status/{0}");

app.UseRouter(routes =>
{
//""
routes.MapGet("", context =>
{
return context.Response.WriteAsync("root path");
}); routes.MapGet("status/{code}", (request, response, routeData) =>
{
var statusCodePagesFeature = request.HttpContext.Features.Get<IStatusCodePagesFeature>();
var code = routeData.Values["code"];
if (statusCodePagesFeature != null && code!=null && code.ToString() == "404")
{
//跳转到自定义的404页面
return request.HttpContext.Render("/views/404.cshtml");
}
else
{
return response.WriteAsync(HtmlEncoder.Default.Encode("状态码:"+ routeData.Values["code"]));
}
});
});

异常错误页

开发异常页面,Asp.net Core自带

app.UseDeveloperExceptionPage();

新增测试路由,抛出空指针异常

env.EnvironmentName = EnvironmentName.Development;
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
else
{
app.UseExceptionHandler("/error");
} app.UseRouter(routes =>
{
//""
routes.MapGet("", context =>
{
return context.Response.WriteAsync("root path");
} //test
routes.MapGet("test", context =>
{
throw new Exception("空指针异常!!!");
});
});

访问http://localhost:57393/test,得到下面的页面

Asp.net Core 入门实战

自定义异常页面

env.EnvironmentName = EnvironmentName.Production;
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
else
{
//自定义异常错误页面
app.UseExceptionHandler("/error");
} app.UseRouter(routes =>
{
//""
routes.MapGet("", context =>
{
return context.Response.WriteAsync("root path");
} //test
routes.MapGet("test", context =>
{
throw new Exception("空指针异常!!!");
}); //自定义异常错误页面
routes.MapGet("error", context =>
{
context.Response.StatusCode = 500;
context.Response.ContentType = "text/html";
var error = context.Features.Get<IExceptionHandlerFeature>();
if (error != null)
{
return context.Response.WriteAsync("<h1>" + HtmlEncoder.Default.Encode("发生了错误: " + error.Error.Messa + "</h1>");
}
else
{
return context.Response.WriteAsync("<h1>" + HtmlEncoder.Default.Encode("Oops! 发生了错误,请联系管理员")"</h1>");
}
});
});

关于响应

会话

Session

新增登陆页面login.cshtml

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
</head>
<body>
<form action="/login" method="post">
<div>
<label>用户名:</label>
<input type="text" name="UserName" />
</div>
<div>
<label>密码:</label>
<input type="password" name="PassWord" />
</div>
<div>
<input type="submit" value="登陆" />
</div>
</form>
</body>
</html>

添加并启用Session,输入用户名和密码,点击登陆,保持Session数据,登陆成功跳转到/home路由页面,访问Session数据,显示当前登陆的用户名

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Routing;
using Microsoft.Extensions.DependencyInjection;
using System;
using System.IO;
using System.Threading.Tasks; namespace Demo
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine(AppContext.BaseDirectory);
var host = new WebHostBuilder()
.UseKestrel()
.UseContentRoot(Directory.GetCurrentDirectory())
.UseStartup<Startup>()
.Build();
host.Run();
}
} class Startup
{
public void ConfigureServices(IServiceCollection services)
{
//启用路由
services.AddRouting();
services.AddMvc();
services.AddSingleton<RazorViewRenderer>();
//增加Session
services.AddSession();
}
public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
app.UseDeveloperExceptionPage(); // 启用Session
app.UseSession(); app.UseRouter(routes =>
{
routes.MapGet("", (request, response, routeData) =>
{
return request.HttpContext.Render("/views/login.cshtml");
}); routes.MapGet("home", context =>
{
string userName = context.Session.GetString("userName");
if (!string.IsNullOrEmpty(userName))
{
return context.Response.WriteAsync("User:" + userName);
}
else
{
context.Response.Redirect("/");
return Task.CompletedTask;
}
}); routes.MapPost("login", context =>
{
var userName = context.Request.Form["UserName"].ToString();
var password = context.Request.Form["PassWord"].ToString();
if (userName.Equals("admin") && password.Equals("123456"))
{
context.Session.SetString("userName", password);
context.Response.Redirect("/home");
return Task.CompletedTask;
}
else
{
throw new Exception("用户名或密码错误");
}
}); });
} }
}

日志

安装Nuget包

$ dotnet add package Microsoft.Extensions.Logging --version 2.0.0
$ dotnet add package Microsoft.Extensions.Logging.Console --version 2.0.0

下载依赖项

$ dotnet restore

添加日志模块

//启用日志
services.AddLogging(builder=> {
//使用控制台日志提供程序
builder.AddConsole();
});

创建ILogger实例

var logger = context.RequestServices.GetService<ILogger<Startup>> ();
//记录日志
logger.LogInformation("before hello world");

日志分类

日志的类别,可以是任意字符串,默认是完全限定的类名,例如: Demo.Startup

日志级别

logger.LogTrace();
logger.LogDebug();
logger.LogInformation();
logger.LogWarning();
logger.LogError();
logger.LogCritical();

日志过滤

给日志分类为 Demo.Startup的日志类别限定最小的日志级别是LogLevel.Information

services.AddLogging(builder=> {
builder.AddFilter("Demo.Startup", LogLevel.Information);
builder.AddConsole();
});

访问更多关于日志类别,级别,模板,过滤,作用域的说明日志类别

配置

添加配置

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Routing;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using System;
using System.Collections.Generic;
using System.IO;
using System.Threading.Tasks; namespace Demo
{
class Program
{
static void Main(string[] args)
{
var configBuilder = new ConfigurationBuilder();
configBuilder.AddInMemoryCollection(new Dictionary<string, string>() {
{ "name","zhangsan"},
{ "age","18"}
});
var config = configBuilder.Build(); var host = new WebHostBuilder()
.UseKestrel()
.UseContentRoot(Directory.GetCurrentDirectory())
.UseConfiguration(config)
.UseStartup<Startup>()
.Build();
host.Run();
}
}
}

读取配置

app.UseRouter(routes =>
{
routes.MapGet("", context =>
{
var config = context.RequestServices.GetService<IConfiguration>();
string name = config["name"];
string age = config["age"];
return context.Response.WriteAsync("name:"+name+",Age:"+age);
});
});

国际化

添加依赖的Nuget包

$ dotnet add package Microsoft.Extensions.Localization --version 2.0.1

下载依赖项

$ dotnet restore

资源文件命名规则

命名规则 {分类名称}.{语言区域名称}.resx

  • 分类名称:默认的分类名称就是类型的FullName,在AssemblyName后的相对路径,比如Demo.Startup,程序集的名称Demo,就剩下了Startup
  • 语言区域名称: 语言区域名称有zh-CN,en-US,更多

特殊条件下你也可以将资源文件和类定义文件放在同一个目录,这样资源文件的分类名称就是{类名称}.{语言区域名称}.resx

添加资源文件

  • 新建 myresources文件夹
  • 新建 Startup.en-US.resx 新增项 name是sayhi,value是 HelloWorld
  • 新建 Startup.zh-CN.resx 新增项 name是sayhi,value是 世界你好

添加本地化

services.AddLocalization(options =>
options.ResourcesPath = "myresources";
});

启用本地化

var cultureList = new List<CultureInfo>() {
new CultureInfo("en-US"),
new CultureInfo("zh-CN")
};
var options = new RequestLocalizationOptions()
{
SupportedCultures = cultureList,
SupportedUICultures = cultureList,
DefaultRequestCulture = new RequestCulture("zh-CN")
};
//新建基于Query String的多语言提供程序
var provider = new QueryStringRequestCultureProvider();
provider.QueryStringKey = "culture";
provider.UIQueryStringKey = "uiculture";
//删除所有多语言提供程序
options.RequestCultureProviders.Clear();
options.RequestCultureProviders.Add(provider);

资源文件读取

var stringLocalizer = context.RequestServices.GetService<IStringLocalizer<Startup>>();
string sayhi = stringLocalizer["sayhi"];

访问 http://localhost:57393/?culture=en-US 切换为英文版本,默认的语言是中文

多语言提供程序

  • 通过Query String,[默认自带]
  • 通过Cookie,[默认自带]
  • 通过Accept-Language header,[默认自带]
  • 通过RouteData

模板格式化

string username="张三";
string localizedString = _localizer["Hello {0}!", username];
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