Meziantou.Framework

Assembly-wide defaults

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Set the defaults

When most IDs of a project need the same options, set them once with [assembly: StronglyTypedIdDefaults], in any file of the project:

[assembly: StronglyTypedIdDefaults(GuidGenerationStrategy = GuidGenerationStrategy.Version7,
                                   GenerateNewtonsoftJsonConverter = false,
                                   GenerateMongoDBBsonSerialization = false,
                                   GenerateSystemComponentModelTypeConverter = false,
                                   GenerateSystemTextJsonConverter = true,
                                   AddCodeGeneratedAttribute = true,
                                   StringComparison = StringComparison.Ordinal,
                                   GenerateToStringAsRecord = true)]

namespace Meziantou.Framework.StronglyTypedId.AssemblyDefaults.Samples;

[StronglyTypedId<Guid>]
public partial struct ProjectId { } // New() uses Guid.CreateVersion7()

[StronglyTypedId<Guid>(GuidGenerationStrategy = GuidGenerationStrategy.Version4)]
public partial struct CustomerId { } // New() uses Guid.NewGuid()

StronglyTypedIdDefaults has a property for each option, with the same name in PascalCase: GenerateSystemTextJsonConverter, GenerateNewtonsoftJsonConverter, GenerateSystemComponentModelTypeConverter, GenerateMongoDBBsonSerialization, AddCodeGeneratedAttribute, StringComparison, GenerateToStringAsRecord and GuidGenerationStrategy. A property you do not set keeps the default value of the option.

Override a default on a type

An option written on [StronglyTypedId] takes precedence over the assembly-wide default. In the example above, ProjectId uses the default Version7 strategy, and CustomerId overrides it with Version4.

Only the options that you write count. A constructor argument written by name (generateNewtonsoftJsonConverter: true) or by position ([StronglyTypedId(typeof(int), true)]) overrides the default; an optional argument that you leave out uses the assembly-wide default, not true.

Scope

  • The defaults apply to the IDs declared in the assembly that has the attribute, not to other projects of the solution. Use a shared file, such as one included by a Directory.Build.props file, to give several projects the same defaults.
  • An assembly has one StronglyTypedIdDefaults attribute at most.
  • GuidGenerationStrategy = GuidGenerationStrategy.Version7 is an error on a framework without Guid.CreateVersion7(), as on a type (MFSTID0002). A GuidGenerationStrategy default has no effect on the IDs that do not wrap a Guid, without a warning.