添加种子数据时，我收到以下错误::'没有为此 DbContext 配置数据库提供程序

问题描述

我收到此错误：

可以通过覆盖“*DbContext.OnConfiguring”方法或在应用程序服务提供者上使用“AddDbContext”来配置提供者。如果使用“AddDbContext”，则还要确保您的 DbContext 类型在其构造函数中接受 DbContextOptions 对象并将其传递给 DbContext 的基本构造函数

种子文件和数据库文件如下。

public static class SeedDatabase
{
    public static void Seed()
    {
        var context = new ShopContext();
        context.MainCategories.AddRange(mainCategories);
        context.SubCategories.AddRange(subCategories);
        context.Categories.AddRange(basicCategories);
        context.Products.AddRange(products);
        context.AddRange(productCategories);

        context.SaveChanges();
    }

    private static BasicCategory[] basicCategories =
    {
        new BasicCategory() {BasicCategoryId = 1,Name = "ELEKTRONİK&BEYAZ EŞYA",},new BasicCategory() {BasicCategoryId = 2,Name = "MODA",}
    };

    private static MainCategory[] mainCategories =
    {
        new MainCategory() {MainCategoryId = 1,Name = "Cep Telefonu ve Aksesuar"},new MainCategory() {MainCategoryId = 2,Name = "Bilgisayar,Tablet"},new MainCategory() {MainCategoryId = 3,Name = "Erkek"},new MainCategory() {MainCategoryId = 4,Name = "Kadın"}
    };

    private static SubCategory[] subCategories =
    {
        new SubCategory() {SubCategoryId = 1,Name = "Cep Telefonu"},new SubCategory() {SubCategoryId = 2,Name = "Cep Telefonu Aksesuar"},new SubCategory() {SubCategoryId = 3,Name = "Kılıf"},new SubCategory() {SubCategoryId = 4,Name = "Şarj Cihazı"},};

    private static Product[] products =
    {
        new Product
        {
            
            Puani = 4.4,KargoUcretsizmi = true,PuanAdedi = 89,ProductId = 1,StokKodu = "5484959",Label = "Samsung S6",Durumu = "Sıfır",Markasi = "Samsung galaxy M51 128 GB (Samsung Türkiye Garantili)",BirkacFarklıSecenegiVarMı = true,PiyasaFiyati = 2600,AlisFiyati = 2400,Fiyat = 2400,KDVOrani = 14,ParBirimi = "tl",IndirimliFiyatMi = true,Indirim = 200,HavaleIndirimOrani = 300,StokAdedi = 5,StokTipi = "cm",GarantiSuresi = 200,Resim1 = "https://productimages.hepsiburada.net/s/43/550/10756209672242.jpg/format:webp",Resim2 = "https://productimages.hepsiburada.net/s/43/550/10756209672242.jpg/format:webp",Resim3 = "https://productimages.hepsiburada.net/s/43/550/10756209672242.jpg/format:webp",Resim4 = "https://productimages.hepsiburada.net/s/43/550/10756209672242.jpg/format:webp",Resim5 = "https://productimages.hepsiburada.net/s/43/550/10756209672242.jpg/format:webp",Resim6 = "https://productimages.hepsiburada.net/s/43/550/10756209672242.jpg/format:webp",Detaylari = "Samsung galaxy M51 128 GB (Samsung Türkiye Garantili Samsung galaxy M51 128 GB (Samsung Türkiye Garantili",Anasayfadami = true,UrunAktifMi = true
        },new Product
        {
            Puani = 4.4,ProductId = 2,StokKodu = "5465465456",Detaylari =
                "Samsung galaxy M51 128 GB (Samsung Türkiye Garantili Samsung galaxy M51 128 GB (Samsung Türkiye Garantili",};

    private static ProductCategory[] productCategories =
    {
        new ProductCategory(){BasicCategory = basicCategories[1],MainCategory = mainCategories[1],SubCategory = subCategories[1],Product = products[0]}
    };
}

数据库文件：

public class ShopContext:IdentityDbContext<UserEntity>
{
    public ShopContext()
    {
    }

    public ShopContext(DbContextOptions<ShopContext> options) : base(options)
    {
    }
 
    public DbSet<UserEntity> usermodels { get; set; }
    public DbSet<Product> Products { get; set; }
    public DbSet<BasicCategory> Categories { get; set; }
    public DbSet<MainCategory> MainCategories { get; set; }
    public DbSet<SubCategory> SubCategories { get; set; }

    public DbSet<Cart> Carts { get; set; }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        base.OnModelCreating(modelBuilder);

        modelBuilder.Entity<Product>().HasKey(x => x.ProductId);
        modelBuilder.Entity<Product>().Property(x => x.ProductId).UseIdentityColumn();
        
        modelBuilder.Entity<BasicCategory>().HasKey(x => x.BasicCategoryId);
        modelBuilder.Entity<BasicCategory>().Property(x => x.BasicCategoryId).UseIdentityColumn();
        
        modelBuilder.Entity<MainCategory>().HasKey(x => x.MainCategoryId);
        modelBuilder.Entity<MainCategory>().Property(x => x.MainCategoryId).UseIdentityColumn();

        modelBuilder.Entity<SubCategory>().HasKey(x => x.SubCategoryId);
        modelBuilder.Entity<SubCategory>().Property(x => x.SubCategoryId).UseIdentityColumn();

        modelBuilder.Entity<ProductCategory>().HasKey(c => new {c.BasicCategoryId,c.ProductId,c.MainCategoryId,c.SubCategoryId});
    }
}

解决方法

删除默认构造函数并使用以下代码，如documentation;

var contextOptions = new DbContextOptionsBuilder<ApplicationDbContext>()
.UseSqlServer(@"Server=(localdb)\mssqllocaldb;Database=Test")
.Options;

using var context = new ApplicationDbContext(contextOptions);

删除默认构造函数的原因是您的 DbContext 必须知道将连接到哪里以及如何连接到数据库。不要忘记使用“using”语句来更好地管理内存。