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ASP.NET Core - 异常处理

在本章中，无涯教程将讨论异常和错误处理，当您的ASP.NET Core应用程序中发生错误时，您可以通过多种方式来处理它们，看看可通过诊断程序包获得的另一中间件，这段中间件将帮助处理错误。

为了模拟错误，转到 app.Run ，如果碰到此中间件时都抛出异常。

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; }  
        
      //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 http://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) { 
         app.UseIISPlatformHandler();  
         app.UseRuntimeInfoPage();  
         
         app.Run(async (context) => { 
            throw new System.Exception("Throw Exception"); 
            var msg=Configuration["message"]; 
            await context.Response.WriteAsync(msg); 
         });  
      }  
        
      //Entry point for the application. 
      public static void Main(string[] args) => WebApplication.Run<Startup>(args); 
   }   
}

它将抛出异常，并带有非常通用的消息，保存 Startup.cs 页并运行您的应用程序。

无涯教程网

您将看到无法加载该资源，出现HTTP 500错误，内部服务器错误，但这不是很有帮助，如果能获取一些异常信息可能会更好。

添加另一个中间件，即 UseDeveloperExceptionPage 。

//This method gets called by the runtime.  
//Use this method to configure the HTTP request pipeline. 
public void Configure(IApplicationBuilder app) { 
   app.UseIISPlatformHandler();  
   app.UseDeveloperExceptionPage(); 
   app.UseRuntimeInfoPage();  
   
   app.Run(async (context) => { 
      throw new System.Exception("Throw Exception"); 
      var msg=Configuration["message"]; 
      await context.Response.WriteAsync(msg); 
   });  
}