实体框架核心迁移自定义历史记录表列

Question

我正在尝试弄清楚如何在迁移历史记录表中添加和设置自定义列的值。 我已经弄清楚了如何使用自定义 SqlServerHistoryRepository 添加列，如下所示：

class MyHistoryRepository : SqlServerHistoryRepository
{
public MyHistoryRepository(HistoryRepositoryDependencies dependencies) : base(dependencies)
{            
}
protected override void ConfigureTable(EntityTypeBuilder<HistoryRow> history)
{
base.ConfigureTable(history);
history.Property<DateTime>("Applied").HasDefaultValue(DateTime.Now);
history.Property<string>("UserStamp");
}
}`

我正在面向 .NET Standard 的库中创建数据层。 我已经为迁移创建了一个IDesignTimeDbContextFactory，如下所示。

public class MyDbContextFactory : IDesignTimeDbContextFactory<MyContext>
{
public MyContext CreateDbContext(string[] args)
{
var optionsBuilder = new DbContextOptionsBuilder<MyContext>();
optionsBuilder.UseSqlServer("connectionString",
ob => ob.MigrationsAssembly(this.GetType().Assembly.GetName().Name))
.ReplaceService<IHistoryRepository, MyHistoryRepository>();
return new MyContext(optionsBuilder.Options);
}
}

如何将用户戳的值传递到迁移历史记录表中？

Answer 1

您可以使用依赖注入将任何服务直接传递到IHistoryRepository的实现中。

例如，要从文件中读取值，您可以执行以下操作：

public class MyHistoryRepository : NpgsqlHistoryRepository
{
private readonly IConfiguration _config;
public MyHistoryRepository(
HistoryRepositoryDependencies dependencies,
IConfiguration config) : base(dependencies)
{
_config = config;
}
protected override void ConfigureTable(EntityTypeBuilder<HistoryRow> history)
{
base.ConfigureTable(history);
history.Property<DateTime>("Applied").HasDefaultValue(DateTime.Now);
history.Property<string>("UserStamp")
.HasDefaultValue(_config["UserStamp"] ?? "");
}
}
public class MyDbContextFactory : IDesignTimeDbContextFactory<MyContext>
{
public MyContext CreateDbContext(string[] args)
{
var services = new ServiceCollection();
IConfiguration config = new ConfigurationBuilder()
.SetBasePath(Directory.GetCurrentDirectory())
.AddJsonFile("config.json")
.Build();
// in your case this would probably be 'AddEntityFrameworkSqlServer'
services.AddEntityFrameworkNpgsql();
services.AddSingleton<IConfiguration>(config);
services.AddScoped<IHistoryRepository, MyHistoryRepository>();
var optionsBuilder = new DbContextOptionsBuilder<MyContext>();
optionsBuilder.UseNpgsql(config.GetConnectionString("DefaultConnection"))
.UseInternalServiceProvider(services.BuildServiceProvider());
return new MyContext(optionsBuilder.Options);
}
}