Configuring Maximum File Upload Size in ASP.NET Core: A Step-by-Step Guide

To increase the maximum upload file size in ASP.NET Core, you need to modify the configuration settings in both the server and application levels. Here's how you can do it:

1. Server-Level Configuration:

   • 1. Open the web.config file in the root directory of your ASP.NET Core application.
   • 2. Locate the <system.webServer> section.
   • 3. Add or update the maxAllowedContentLength attribute in the <requestLimits> element to specify the maximum allowed content length in bytes. For example:

     xml
     <system.webServer>
       <security>
         <requestFiltering>
           <requestLimits maxAllowedContentLength="52428800" /> <!-- 50 MB -->
         </requestFiltering>
       </security>
     </system.webServer>

2. Application-Level Configuration:

   • 1. Open the Startup.cs file in your ASP.NET Core application.

   • 2. In the ConfigureServices method, add the following code to configure the maximum request size:

     csharp
     public void ConfigureServices(IServiceCollection services)
     {
         // ...
         services.Configure<IISServerOptions>(options =>
         {
             options.MaxRequestBodySize = int.MaxValue; // Set to the desired maximum size
         });
         // ...
     }

     Alternatively, you can configure the maximum request size using the webBuilder in the CreateHostBuilder method of Program.cs:

     csharp
     public static IHostBuilder CreateHostBuilder(string[] args) =>
         Host.CreateDefaultBuilder(args)
             .ConfigureWebHostDefaults(webBuilder =>
             {
                 webBuilder.ConfigureKestrel(options =>
                 {
                     options.Limits.MaxRequestBodySize = int.MaxValue; // Set to the desired maximum size
                 });
                 webBuilder.UseStartup<Startup>();
             });

     Note: Remember to adjust the int.MaxValue value to the desired maximum file size limit in bytes.

By making these configurations, you can increase the maximum file upload size in ASP.NET Core to accommodate larger files. Ensure that you set appropriate values considering your application's requirements and server resources.