Rules of WPF:

❌ Avoid the WPF Designer to eliminate a category of confusing bugs
❌ Don't rely on Margin as the primary tool for layouts
❌ Avoid writing UserControls or subclassing to extend a default control -- use Behaviors instead (Microsoft.Xaml.Behaviors.Wpf)

✅ Write XAML by hand and autoformat with "Ctrl K,D" or XAML Styler
✅ Rely upon XAML Hot Reload to design your app's UI at runtime
✅ Use layout controls (Grid, DockPanel, etc) to support proper resizing
✅ Use data binding to eliminate glue code and state synchronization issues
✅ Use collection controls and DataTemplate to dynamically create lists of controls
✅ Learn MVVM to create maintainable apps
✅ Use the Dispatcher to update controls from non-UI threads
✅ WPF's default controls can be easily modernized via $wpfuilibs
✅ Include relevant XAML, code-behind, and ViewModel code for questions when possible

Rules of WPF:

❌ Avoid the WPF Designer to eliminate a category of confusing bugs
❌ Don't rely on Margin as the primary tool for layouts
❌ Avoid writing UserControls or subclassing to extend a default control -- use Behaviors instead (Microsoft.Xaml.Behaviors.Wpf)

✅ Write XAML by hand and autoformat with "Ctrl K,D" or XAML Styler
✅ Rely upon XAML Hot Reload to design your app's UI at runtime
✅ Use layout controls (Grid, DockPanel, etc) to support proper resizing
✅ Use data binding to eliminate glue code and state synchronization issues
✅ Use collection controls and DataTemplate to dynamically create lists of controls
✅ Learn MVVM to create maintainable apps
✅ Use the Dispatcher to update controls from non-UI threads
✅ WPF's default controls can be easily modernized via $wpfuilibs
✅ Include relevant XAML, code-behind, and ViewModel code for questions when possible

{
  "My": {
    "Foo": {
      "Kix": 5
    }
  }
}

{
  "My": {
    "Foo": {
      "Kix": 5
    }
  }
}

public class FooOptions
{
  public const string SectionName = "My:Foo";

  public string Bar {get;set;} = "default value for bar";
  public int Kix {get;set;} = -1;
  public DateTime? Pouet {get;set;} = default;
}

public class FooOptions
{
  public const string SectionName = "My:Foo";

  public string Bar {get;set;} = "default value for bar";
  public int Kix {get;set;} = -1;
  public DateTime? Pouet {get;set;} = default;
}

namespace Microsoft.Extensions.DependencyInjection; // <==== recommanded for service.Add so that you don't clutter Startup file

public class FooServiceCollectionExtensions
{
  public static IServiceCollection AddFoo(this IServiceCollection services) =>
    services
      .AddOptions<FooOptions>()
      .BindConfiguration(FooOptions.SectionName)
      .Validate(options => options.Kix >= 0, $"The configuration key '{FooOptions.SectionName}:{nameof(Kix)}' cannot be negative")
      ;

  public static IServiceCollection AddFoo(this IServiceCollection services, Action<FooOptions> configure) =>
    services
      .AddFoo()
      .Configure(configure);

namespace Microsoft.Extensions.DependencyInjection; // <==== recommanded for service.Add so that you don't clutter Startup file

public class FooServiceCollectionExtensions
{
  public static IServiceCollection AddFoo(this IServiceCollection services) =>
    services
      .AddOptions<FooOptions>()
      .BindConfiguration(FooOptions.SectionName)
      .Validate(options => options.Kix >= 0, $"The configuration key '{FooOptions.SectionName}:{nameof(Kix)}' cannot be negative")
      ;

  public static IServiceCollection AddFoo(this IServiceCollection services, Action<FooOptions> configure) =>
    services
      .AddFoo()
      .Configure(configure);

services.AddFoo();
// or
services.AddFoo(fooOptions => fooOptions.Kix = 12);

services.AddFoo();
// or
services.AddFoo(fooOptions => fooOptions.Kix = 12);

public class Bar
{
  private readonly FooOptions _fooOptions;

  // .Value in ctor is fine only if it's always ever a non-changing value (no reload and/or no scoped resolution)
  public Bar(IOptions<FooOptions> fooOptions)
    => _fooOptions = fooOptions.Value;
}

public class Bar
{
  private readonly FooOptions _fooOptions;

  // .Value in ctor is fine only if it's always ever a non-changing value (no reload and/or no scoped resolution)
  public Bar(IOptions<FooOptions> fooOptions)
    => _fooOptions = fooOptions.Value;
}