C# Syntax =>

Question

PLEASE can somebody rewrite the below code for me without using the => operator. I'm trying to understand what it is doing and struggling. Have spent a lot of time but still can't get it. Thanks in advance:

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

Answer 1

To replace the first “=>”, move the caret to this location and press <Ctrl+.>, then select “Use block body for methods”. The result will be probably this:

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

To replace the second “=>” too, try something like this:

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

Answer 2

The method ConfigureWebHostDefaults is expecting an action. So basically webBuilder is an instance of IHostBuilder which you use to setup the defaults for the web host. In this case it is setting the startup class.

https://learn.microsoft.com/en-us/dotnet/api/microsoft.aspnetcore.hosting.webhostbuilderextensions.usestartup?view=aspnetcore-5.0#Microsoft_AspNetCore_Hosting_WebHostBuilderExtensions_UseStartup__1_Microsoft_AspNetCore_Hosting_IWebHostBuilder_