Class DbContextBuilder<T>

Uses the Builder pattern to create instances of DbContext types seeded with specified data.

Inheritance

object

DbContextBuilder<T>

Implements

IDisposable

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: Wolfgang.DbContextBuilderCore

Assembly: Wolfgang.DbContextBuilder-Core.dll

Syntax

public class DbContextBuilder<T> : IDisposable where T : DbContext

Type Parameters

Name	Description
T	The concrete DbContext type to construct.

Remarks

When using the SQLite provider, the builder holds an open SQLite in-memory connection. Dispose the builder only after all DbContext instances returned by BuildAsync() are no longer in use, as disposing the builder closes the shared connection and destroys the in-memory database.

Methods

BuildAsync()

Creates a new instance of T seeded with the specified data.

Declaration

public Task<T> BuildAsync()

Returns

Type	Description
Task<T>	A new instance of T.

Exceptions

Type	Condition
ObjectDisposedException	The builder has been disposed.

Dispose()

Disposes the underlying database context creator, releasing any held resources (e.g., the SQLite in-memory connection).

Declaration

public void Dispose()

Dispose(bool)

Releases unmanaged and optionally managed resources.

Declaration

protected virtual void Dispose(bool disposing)

Parameters

Type	Name	Description
bool	disposing	true to release both managed and unmanaged resources.

SeedWithRandom<TEntity>(int)

Populates the specified DbSet with random entities of type TEntity.

Declaration

public DbContextBuilder<T> SeedWithRandom<TEntity>(int count) where TEntity : class

Parameters

Type	Name	Description
int	count	The number of items to create

Returns

Type	Description
DbContextBuilder<T>	DbContextBuilder<T>

Type Parameters

Name	Description
TEntity	The type of entity to create

Remarks

Foreign keys on the generated entities are reconciled against the model when the context is built: a required FK is wired to a seeded principal of its type (so seed the principals too), and an optional FK with no seeded principal is set to null. The FK values on a randomly-seeded entity are therefore not the raw random values produced by the creator. Entities added via SeedWith are never reconciled.

Exceptions

Type	Condition
ArgumentOutOfRangeException	count is less than 1

SeedWithRandom<TEntity>(int, Func<TEntity, int, TEntity>)

Populates the specified DbSet with random entities of type TEntity.

Declaration

public DbContextBuilder<T> SeedWithRandom<TEntity>(int count, Func<TEntity, int, TEntity> func) where TEntity : class

Parameters

Type	Name	Description
int	count	The number of items to create
Func<TEntity, int, TEntity>	func	A function that takes a TEntity and the index number of the entity and returns an updated TEntity

Returns

Type	Description
DbContextBuilder<T>	DbContextBuilder<T>

Type Parameters

Name	Description
TEntity	The type of entity to create

Remarks

Foreign keys on the generated entities are reconciled against the model when the context is built: a required FK is wired to a seeded principal of its type (so seed the principals too), and an optional FK with no seeded principal is set to null. The FK values on a randomly-seeded entity are therefore not the raw random values produced by the creator. Entities added via SeedWith are never reconciled.

Exceptions

Type	Condition
ArgumentOutOfRangeException	count is less than 1

SeedWithRandom<TEntity>(int, Func<TEntity, TEntity>)

Populates the specified DbSet with random entities of type TEntity.

Declaration

public DbContextBuilder<T> SeedWithRandom<TEntity>(int count, Func<TEntity, TEntity> func) where TEntity : class

Parameters

Type	Name	Description
int	count	The number of items to create
Func<TEntity, TEntity>	func	A function that takes a TEntity and returns an updated TEntity

Returns

Type	Description
DbContextBuilder<T>	DbContextBuilder<T>

Type Parameters

Name	Description
TEntity	The type of entity to create

Remarks

Foreign keys on the generated entities are reconciled against the model when the context is built: a required FK is wired to a seeded principal of its type (so seed the principals too), and an optional FK with no seeded principal is set to null. The FK values on a randomly-seeded entity are therefore not the raw random values produced by the creator. Entities added via SeedWith are never reconciled.

Exceptions

Type	Condition
ArgumentOutOfRangeException	count is less than 1

SeedWith<TEntity>(IEnumerable<TEntity>)

Populates the specified DbSet with the provided entities.

Declaration

public DbContextBuilder<T> SeedWith<TEntity>(IEnumerable<TEntity> entities) where TEntity : class

Parameters

Type	Name	Description
IEnumerable<TEntity>	entities	The entities to populate the database with

Returns

Type	Description
DbContextBuilder<T>	DbContextBuilder<T>

Type Parameters

Name	Description
TEntity

Remarks

Insertion order across distinct entity types is not guaranteed — the builder accumulates seeds in a single list and EF's SaveChangesAsync orders the inserts by FK dependency, not by the order SeedWith calls were made. For scenarios where the order of two same-type rows matters (e.g. identity-generated keys), pass them in the desired order within a single SeedWith call. Inheritance mapping (TPH / TPT / TPC) is supported via entity.GetType(); the runtime type determines which DbSet receives the row.

Exceptions

Type	Condition
ArgumentNullException	entities is null
ArgumentException	entities contains a null item
ArgumentException	entities contains a string

SeedWith<TEntity>(TEntity)

Populates the specified DbSet with a single entity. Equivalent to calling the params-array overload with one element, but avoids the per-call allocation of a one-element array — useful in tests that seed many single rows.

Declaration

public DbContextBuilder<T> SeedWith<TEntity>(TEntity entity) where TEntity : class

Parameters

Type	Name	Description
TEntity	entity	The entity to populate the database with.

Returns

Type	Description
DbContextBuilder<T>	The builder, for chaining.

Type Parameters

Name	Description
TEntity

Exceptions

Type	Condition
ArgumentNullException	entity is null.
ArgumentException	entity is a string instance (matches the params overload's rejection regardless of how TEntity was inferred).

SeedWith<TEntity>(params TEntity[])

Populates the specified DbSet with the provided entities.

Declaration

public DbContextBuilder<T> SeedWith<TEntity>(params TEntity[] entities) where TEntity : class

Parameters

Type	Name	Description
TEntity[]	entities	The entities to populate the database with

Returns

Type	Description
DbContextBuilder<T>	DbContextBuilder<T>

Type Parameters

Name	Description
TEntity

Exceptions

Type	Condition
ArgumentNullException	entities is null
ArgumentException	entities contains a null item
ArgumentException	entities contains a string

UseCustomRandomEntityCreator(ICreateRandomEntities)

Allows the user to specify their own implementation of ICreateRandomEntities for creating random entities.

Declaration

public DbContextBuilder<T> UseCustomRandomEntityCreator(ICreateRandomEntities creator)

Parameters

Type	Name	Description
ICreateRandomEntities	creator	The creator to use

Returns

Type	Description
DbContextBuilder<T>	DbContextBuilder<T>

UseDbContextOptionsBuilder(DbContextOptionsBuilder<T>)

Specifies a specific DbContextOptionsBuilder<TContext> instance to use when creating the DbContext.

Declaration

public DbContextBuilder<T> UseDbContextOptionsBuilder(DbContextOptionsBuilder<T> dbContextOptionsBuilder)

Parameters

Type	Name	Description
DbContextOptionsBuilder<T>	dbContextOptionsBuilder	The options builder to use when creating the DbContext.

Returns

Type	Description
DbContextBuilder<T>	DbContextBuilder<T>

Exceptions

Type	Condition
ArgumentNullException	dbContextOptionsBuilder is null.

UseDiagnosticOutput(Action<string>)

Routes diagnostic output to writeLine: EF Core logs (including the generated SQL) produced while creating and seeding the database, plus a one-line summary of how many entity rows were seeded. Pass your test framework's output sink — for example UseDiagnosticOutput(testOutputHelper.WriteLine) in xUnit — so the seeded context is visible in the test log when an assertion fails.

Declaration

public DbContextBuilder<T> UseDiagnosticOutput(Action<string> writeLine)

Parameters

Type	Name	Description
Action<string>	writeLine	Receives each diagnostic line.

Returns

Type	Description
DbContextBuilder<T>	DbContextBuilder<T>

Exceptions

Type	Condition
ArgumentNullException	writeLine is null.

UseInMemory()

Instructs the builder to use InMemory as the database provider.

Declaration

public DbContextBuilder<T> UseInMemory()

Returns

Type	Description
DbContextBuilder<T>	DbContextBuilder<T>

Remarks

Provider selection is last-write-wins — calling UseInMemory() after a previous call to either UseInMemory() or a SQLite extension overrides the earlier choice. Choose one provider per builder.

UseSeedProfile(ISeedProfile<T>)

Applies a reusable ISeedProfile<T> to this builder. Profiles bundle a complete set of seed data so the same setup can be shared across many tests with a single call. Multiple profiles can be applied; their seed data accumulates.

Declaration

public DbContextBuilder<T> UseSeedProfile(ISeedProfile<T> profile)

Parameters

Type	Name	Description
ISeedProfile<T>	profile	The seed profile to apply.

Returns

Type	Description
DbContextBuilder<T>	DbContextBuilder<T>

Exceptions

Type	Condition
ArgumentNullException	profile is null.

Implements

IDisposable

Extension Methods

DbContextBuilderSqliteExtensions.UseSqliteForMsSqlServer<TDbContext>(DbContextBuilder<TDbContext>)

DbContextBuilderSqliteExtensions.UseSqlite<TDbContext>(DbContextBuilder<TDbContext>)