C#•2y ago

❔ How to log using hosts?

using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;

var builder = new HostApplicationBuilder();
builder.Logging.ClearProviders();
builder.Logging.AddConsole();
builder.Services.AddLogging();

using var host = builder.Build();

var logger = host.Services.GetRequiredService<ILogger>();

logger.LogInformation("🙂");

await host.RunAsync();

using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;

var builder = new HostApplicationBuilder();
builder.Logging.ClearProviders();
builder.Logging.AddConsole();
builder.Services.AddLogging();

using var host = builder.Build();

var logger = host.Services.GetRequiredService<ILogger>();

logger.LogInformation("🙂");

await host.RunAsync();

the error is on when I try to get the logger service:

Unhandled exception. System.InvalidOperationException: No service for type 'Microsoft.Extensions.Logging.ILogger' has been registered.

i thought i had already registered the logging service: builder.Services.AddLogging();

8 Replies

Pobiega•2y ago

iirc that logger takes a ILogger<YourClass> ie, you must resolve it as generic over the class that resolves it. in this case, Program

intOP•2y ago

var logger = host.Services.GetRequiredService<ILogger<Program>>(); works thx also, another question, what's the use of using var in this code? it works fine without using

Pobiega•2y ago

disposing the host when the method ends but obviously, the program ends when the method ends so not much point here

intOP•2y ago

so you suggest i remove the using?

Pobiega•2y ago

intOP•2y ago

but you said there was no point of it

Pobiega•2y ago

yeah, but it also doesnt do anything bad.. and it gets you in the habit of using it its only pointless in Main, since when main ends... in other methods is very much useful

Accord•2y ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

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❔ How to log using hosts?