C#•17mo ago

❔ Exception while using .BindConfiguration instead of .Configure

Hello ! I need some help to understand why I get an

System.InvalidOperationException

System.InvalidOperationException

while I am using Option Pattern (https://learn.microsoft.com/en-us/aspnet/core/fundamentals/configuration/options?view=aspnetcore-7.0) with dependency injection. The exception :

System.InvalidOperationException: No constructor for type 'Microsoft.Extensions.Options.ConfigurationChangeTokenSource`1[CustomOptions]' can be instantiated using services from the service container and default values.

System.InvalidOperationException: No constructor for type 'Microsoft.Extensions.Options.ConfigurationChangeTokenSource`1[CustomOptions]' can be instantiated using services from the service container and default values.

My tests are using a custom helper which iterate through a IServiceCollection to retrieve service from default IoC by using IServiceProvider.GetService( ServiceDescriptor.ServiceType). At the beginning I was registering my options this way (which cause the exception spoken above) :

services.AddOptions<CustomOptions>()
  .BindConfiguration(CustomOptions.SectionName);

services.AddOptions<CustomOptions>()
  .BindConfiguration(CustomOptions.SectionName);

I changed the registration for this way (which work perfect) :

services.AddOptions<CustomOptions>()
  .Configure<IConfiguration>((options, configuration) =>
    {
      const string sectionName = CustomOptions.SectionName;
      var section = configuration.GetSection(sectionName);

      if (!section.Exists())
        throw new OptionsValidationException(sectionName, typeof(CustomOptions),
          new[] { $"Missing section {sectionName}." });

      section.Bind(options);
})

services.AddOptions<CustomOptions>()
  .Configure<IConfiguration>((options, configuration) =>
    {
      const string sectionName = CustomOptions.SectionName;
      var section = configuration.GetSection(sectionName);

      if (!section.Exists())
        throw new OptionsValidationException(sectionName, typeof(CustomOptions),
          new[] { $"Missing section {sectionName}." });

      section.Bind(options);
})

The difference on the code from .BindConfiguration and .Configure : - .BindConfiguration use this instruction:

optionsBuilder.Services.AddSingleton<IOptionsChangeTokenSource<TOptions>, ConfigurationChangeTokenSource<TOptions>>();

optionsBuilder.Services.AddSingleton<IOptionsChangeTokenSource<TOptions>, ConfigurationChangeTokenSource<TOptions>>();

-.Configure use this instructio :

Services.AddTransient<IConfigureOptions<TOptions>>(sp =>
  new ConfigureNamedOptions<TOptions, TDep>(Name, sp.GetRequiredService<TDep>(), configureOptions));

Services.AddTransient<IConfigureOptions<TOptions>>(sp =>
  new ConfigureNamedOptions<TOptions, TDep>(Name, sp.GetRequiredService<TDep>(), configureOptions));

Can someone explain the difference and why the first one throw an exception please ? Thank you

Options pattern in ASP.NET Core

Discover how to use the options pattern to represent groups of related settings in ASP.NET Core apps.

3 Replies

Accord•17mo ago

Looks like nothing has happened here. I will mark this as stale and this post will be archived until there is new activity.

backtrack5r3OP•17mo ago

Hi, someon can up ? thanks !

Accord•17mo 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.

Gaming

Programming

❔ Exception while using .BindConfiguration instead of .Configure