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[英]Can "Script-Migration" create the database in .NET Entity Framework Core?
[英]Cannot create migration script using Entity Framework
(這兩個在線資源都沒有幫助,所以我創建了一個新線程。)
我對運行以下命令創建遷移腳本時收到的錯誤感到困惑:
dotnet ef migrations add InitialCreate -v
當我的dbcontext有無參數構造函數時,我收到以下錯誤:
沒有為此DbContext配置數據庫提供程序。
當我刪除無參數構造函數時,它抱怨我應該把它放回去:
沒有為此對象定義的無參數構造函數
我將dbcontext定義為:
public class ItemContext : DbContext
{
public ItemContext(DbContextOptions<ItemContext> options) : base(options)
{
}
public DbSet<Item> Tools { set; get; }
protected override void OnModelCreating(ModelBuilder builder)
{
builder.ApplyConfiguration(new ToolItemEntityTypeConfiguration());
}
}
該服務定義為:
public IServiceProvider ConfigureServices(IServiceCollection services)
{
services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
services.AddCustomDbContext(Configuration);
var container = new ContainerBuilder();
container.Populate(services);
return new AutofacServiceProvider(container.Build());
}
...
public static class CustomExtensionMethods
{
public static IServiceCollection AddCustomDbContext(this IServiceCollection services, IConfiguration configuration)
{
services.AddDbContext<ItemContext>(options =>
{
options.UseSqlServer(configuration.GetConnectionString("DefaultConnection"),
sqlServerOptionsAction: sqlOptions =>
{
sqlOptions.MigrationsAssembly(typeof(Startup).GetTypeInfo().Assembly.GetName().Name);
sqlOptions.EnableRetryOnFailure(maxRetryCount: 10, maxRetryDelay: TimeSpan.FromSeconds(30), errorNumbersToAdd: null);
});
options.ConfigureWarnings(warnings => warnings.Throw(RelationalEventId.QueryClientEvaluationWarning));
});
return services;
}
}
我想這行代碼
public ItemContext(DbContextOptions<ItemContext> options) : base(options)
{
}
應該改為
public ItemContext(DbContextOptions options) : base(options)
{
}
如果這不起作用,請嘗試在Startup.cs中注冊它
services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
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