ASP0009: Do not use Configure with WebApplicationBuilder.WebHost

Cause

Configure can't be used with the WebHost property on WebApplicationBuilder.

Rule description

The WebApplicationBuilder doesn't support configuring the WebHost before build using the Configure extension method.

var builder = WebApplication.CreateBuilder(args);

builder.WebHost.Configure(webHostBuilder => {
    webHostBuilder.UseContentRootPath(Path.Combine(Directory.GetCurrentDirectory(), "myContentRoot"));
});

var app = builder.Build();

app.Run();

How to fix violations

To fix a violation of this rule, configure the WebHost directly on the WebApplicationBuilder. For example, instead of setting the content root path via Configure.

var builder = WebApplication.CreateBuilder(args);

builder.WebHost.Configure(webHostBuilder =>
{
    webHostBuilder.UseContentRoot(Path.Combine(Directory.GetCurrentDirectory(), "myContentRoot"));
});

var app = builder.Build();

app.Run();

Configure the content root path directly on the WebApplicationBuilder.

var builder = WebApplication.CreateBuilder(args);

builder.WebHost.UseContentRoot(Path.Combine(Directory.GetCurrentDirectory(), "myContentRoot"));

var app = builder.Build();

app.Run();

When to suppress warnings

Do not suppress a warning from this rule. A misconfigured application can result in unexpected behavior at runtime.