无涯教程-ASP.NET Core - 配置文件在本章中，无涯教程将讨论与ASP.NET Core项目相关的配置，在S

在本章中，无涯教程将讨论与ASP.NET Core项目相关的配置，在Solution Explorer中，您将看到Startup.cs文件。如果您使用过ASP.NET Core的早期版本，则可能希望看到一个global.asax文件，该文件是您可以在Web应用程序启动期间编写要执行的代码的地方。

您还希望看到一个web.config文件，其中包含应用程序执行所需的所有配置参数。
在ASP.NET Core中，这些文件都消失了，而是从Startup.cs加载配置和启动代码。
文件中有一个Startup类，在该类中，您可以配置应用程序，甚至可以配置配置源。

这是 Startup.cs文件中的默认实现。

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Threading.Tasks; 
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
namespace FirstAppDemo {
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 go.microsoft.com/fwlink/?Lin… 
public void ConfigureServices(IServiceCollection services) {
}
  </span><span class="com">//This method gets called by the runtime. Use this method to configure </span><span class="pln">
  </span><span class="com">//the HTTP request pipeline.</span><span class="pln">
  </span><span class="kwd">public</span><span class="pln"> </span><span class="kwd">void</span><span class="pln"> </span><span class="typ">Configure</span><span class="pun">(</span><span class="typ">IApplicationBuilder</span><span class="pln"> app</span><span class="pun">,</span><span class="pln"> </span><span class="typ">IHostingEnvironment</span><span class="pln"> env</span><span class="pun">,</span><span class="pln"> 
     </span><span class="typ">ILoggerFactory</span><span class="pln"> loggerFactory</span><span class="pun">)</span><span class="pln"> </span><span class="pun">{</span><span class="pln"> 
     loggerFactory</span><span class="pun">.</span><span class="typ">AddConsole</span><span class="pun">();</span><span class="pln">  
     
     </span><span class="kwd">if</span><span class="pln"> </span><span class="pun">(</span><span class="pln">env</span><span class="pun">.</span><span class="typ">IsDevelopment</span><span class="pun">())</span><span class="pln"> </span><span class="pun">{</span><span class="pln"> 
        app</span><span class="pun">.</span><span class="typ">UseDeveloperExceptionPage</span><span class="pun">();</span><span class="pln"> 
     </span><span class="pun">}</span><span class="pln">  
     app</span><span class="pun">.</span><span class="typ">Run</span><span class="pun">(</span><span class="kwd">async</span><span class="pln"> </span><span class="pun">(</span><span class="pln">context</span><span class="pun">)</span><span class="pln"> </span><span class="pun">=&gt;</span><span class="pln"> </span><span class="pun">{</span><span class="pln"> 
        </span><span class="kwd">await</span><span class="pln"> context</span><span class="pun">.</span><span class="typ">Response</span><span class="pun">.</span><span class="typ">WriteAsync</span><span class="pun">(</span><span class="str">"Hello World!"</span><span class="pun">);</span><span class="pln"> 
     </span><span class="pun">});</span><span class="pln"> 
  </span><span class="pun">}</span><span class="pln"> 

}
}

在Startup类中，有两种方法将完成大部分工作。

在Solution Explorer 中，右键单击您的项目节点，然后选择 Add→New Item。

在左窗格中，选择 Installed→Code ，然后在中间窗格中，选择JSON File，将此文件命名为 AppSettings.json ，然后单击 Add 按钮，如上面的屏幕截图所示。

也可以让程序从文件中读取文本，而不是使用Hello World!Startup.cs中的字符串，在 AppSettings.json文件中添加以下代码。

{ 
   "message": "Hello, World! this message is from configuration file..." 
}

现在，需要从Startup.cs文件访问此消息。这是 Startup.cs 文件的实现，该文件将从JSON文件读取以上消息。

using Microsoft.AspNet.Builder; 
using Microsoft.AspNet.Hosting; 
using Microsoft.AspNet.Http; 
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Configuration;
namespace FirstAppDemo {
public class Startup {
public Startup() {
var builder = new ConfigurationBuilder()

.AddJsonFile("AppSettings.json");
Configuration = builder.Build();
}

public IConfiguration Configuration { get; set; }
  </span><span class="com">//This method gets called by the runtime. </span><span class="pln">
  </span><span class="com">//Use this method to add services to the container. </span><span class="pln">
  </span><span class="com">//For more information on how to configure your application, </span><span class="pln">
  </span><span class="com">//visit http://go.microsoft.com/fwlink/?LinkID=398940 </span><span class="pln">
  </span><span class="kwd">public</span><span class="pln"> </span><span class="kwd">void</span><span class="pln"> </span><span class="typ">ConfigureServices</span><span class="pun">(</span><span class="typ">IServiceCollection</span><span class="pln"> services</span><span class="pun">)</span><span class="pln"> </span><span class="pun">{</span><span class="pln"> 
  </span><span class="pun">}</span><span class="pln">  
  
  </span><span class="com">//This method gets called by the runtime.  </span><span class="pln">
  </span><span class="com">//Use this method to configure the HTTP request pipeline. </span><span class="pln">
  </span><span class="kwd">public</span><span class="pln"> </span><span class="kwd">void</span><span class="pln"> </span><span class="typ">Configure</span><span class="pun">(</span><span class="typ">IApplicationBuilder</span><span class="pln"> app</span><span class="pun">)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
     app</span><span class="pun">.</span><span class="typ">UseIISPlatformHandler</span><span class="pun">();</span><span class="pln">  
     app</span><span class="pun">.</span><span class="typ">Run</span><span class="pun">(</span><span class="kwd">async</span><span class="pln"> </span><span class="pun">(</span><span class="pln">context</span><span class="pun">)</span><span class="pln"> </span><span class="pun">=&gt;</span><span class="pln"> </span><span class="pun">{</span><span class="pln"> 
        </span><span class="kwd">var</span><span class="pln"> msg </span><span class="pun">=</span><span class="pln"> </span><span class="typ">Configuration</span><span class="pun">[</span><span class="str">"message"</span><span class="pun">];</span><span class="pln"> 
        </span><span class="kwd">await</span><span class="pln"> context</span><span class="pun">.</span><span class="typ">Response</span><span class="pun">.</span><span class="typ">WriteAsync</span><span class="pun">(</span><span class="pln">msg</span><span class="pun">);</span><span class="pln"> 
     </span><span class="pun">});</span><span class="pln">  
  </span><span class="pun">}</span><span class="pln">  
    
  </span><span class="com">//Entry point for the application. </span><span class="pln">
  </span><span class="kwd">public</span><span class="pln"> </span><span class="kwd">static</span><span class="pln"> </span><span class="kwd">void</span><span class="pln"> </span><span class="typ">Main</span><span class="pun">(</span><span class="kwd">string</span><span class="pun">[]</span><span class="pln"> args</span><span class="pun">)</span><span class="pln"> </span><span class="pun">=</span><span class="lit">7gt</span><span class="pun">;</span><span class="pln"> </span><span class="typ">WebApplication</span><span class="pun">.</span><span class="typ">Run</span><span class="pun">&lt;</span><span class="typ">Startup</span><span class="pun">&gt;(</span><span class="pln">args</span><span class="pun">);</span><span class="pln"> 

}
}

现在让无涯教程运行该应用程序。一旦运行该应用程序，它将产生以下输出。

无涯教程-ASP.NET Core - 配置文件

参考链接