【发布时间】：2011-09-14 16:58:40
【问题描述】：
我使用的是 EF 4.1 Code First 设置，这里是实体。
public class Vendor
{
public int VendorId { get; set; }
public string Name { get; set; }
public virtual ICollection<VendorProduct> VendorProducts { get; set; }
}
public class VendorProduct
{
public int VendorProductId { get; set; }
public int ProductId { get; set; }
public int VendorId { get; set; }
public string VendorProductNumber { get; set; }
public int Quantity { get; set; }
public decimal SalesPrice { get; set; }
public Product Product { get; set; }
public Vendor Vendor { get; set; }
}
public class Product
{
public int ProductId { get; set; }
public string Name { get; set; }
public string Manufacturer { get; set; }
public string ManufacturerNumber { get; set; }
public string UPC { get; set; }
public decimal SalesPrice { get; set; }
public string Description { get; set; }
public virtual ICollection<VendorProduct> VendorProducts { get; set; }
}
这里是配置
public class VendorConfiguration : EntityTypeConfiguration<Vendor>
{
public VendorConfiguration()
{
Property(p => p.Name).IsOptional().HasMaxLength(128);
}
}
public class ProductConfiguration : EntityTypeConfiguration<Product>
{
public ProductConfiguration()
{
//HasKey(p => p.ProductId);
//HasMany(p => p.Images).WithOptional();
Property(p => p.Name).IsOptional().HasMaxLength(128);
Property(p => p.Manufacturer).IsOptional().HasMaxLength(64);
Property(p => p.ManufacturerNumber).IsOptional().HasMaxLength(32);
Property(p => p.UPC).IsOptional().HasMaxLength(32);
Property(p => p.SalesPrice).IsOptional();
}
}
public VendorProductConfiguration()
{
//HasKey(v => v.VendorProductId);
Property(o => o.Quantity).IsRequired();
Property(o => o.SalesPrice).IsRequired();
Property(o => o.VendorId).IsRequired();
Property(o => o.ProductId).IsRequired();
Property(o => o.VendorProductNumber).IsOptional().HasMaxLength(50);
HasRequired(o => o.Product).WithMany(p => p.VendorProducts).HasForeignKey(o => o.ProductId).WillCascadeOnDelete(false);
}
这里是 DbContext。
public class UbidContext : DbContext
{
public IDbSet<Product> Products { get; set; }
public IDbSet<Vendor> Vendors { get; set; }
public IDbSet<VendorProduct> VendorProducts { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
// Add any configuration or mapping stuff here
modelBuilder.Configurations.Add(new VendorConfiguration());
modelBuilder.Configurations.Add(new VendorProductConfiguration());
modelBuilder.Configurations.Add(new ProductConfiguration());
}
public void Seed(UbidContext context)
{
//Create our indexes
context.Database.ExecuteSqlCommand("CREATE INDEX IX_Products_Name ON Products (Name)");
context.Database.ExecuteSqlCommand("CREATE INDEX IX_Products_Manufacturer ON Products (Manufacturer)");
context.Database.ExecuteSqlCommand("CREATE INDEX IX_Products_ManufacturerNumber ON Products (ManufacturerNumber)");
context.Database.ExecuteSqlCommand("CREATE INDEX IX_Products_UPC ON Products (UPC)");
//Add vendors to the database
AddVendors(context);
context.SaveChanges();
//Add products to the database
AddProducts(context);
context.SaveChanges();
//Add vendor products to the database
AddVendorProducts(context);
}
private static void AddVendors(UbidContext context)
{
new List<Vendor>
{
new Vendor()
{
Name = "TestVendor1",
},
new Vendor()
{
Name = "TestVendor2",
},
new Vendor()
{
Name = "TestVendor3",
}
}.ForEach(v => context.Vendors.Add(v));
}
private static void AddProducts(UbidContext context)
{
Image[] images = new Image[1];
images[0] = new Image
{
Url = "http://content.etilize.com/Thumbnail/10006997.jpg"
};
new List<Product>
{
new Product()
{
Manufacturer = "StarTech.com",
ManufacturerNumber = "SV211K",
Name = "StarTech.com SV211K KVM Switch - 2 x 1 - 2 x HD-15 Video",
UPC = "SV211K",
Images = images
},
new Product()
{
Manufacturer = "Targus Group International",
ManufacturerNumber = "CBT300",
Name = "Targus BlackTop Standard Notebook Case - Clamshell - Carrying Strap - 5 Pocket - Nylon - Black, Blue",
UPC = "CBT300"
},
new Product()
{
Manufacturer = "Lenovo Group Limited",
ManufacturerNumber = "31P8700",
Name = "Lenovo Optical ScrollPoint Pro Mouse - Optical - USB, PS/2",
UPC = "31P8700"
},
new Product()
{
Manufacturer = "Epson Corporation",
ManufacturerNumber = "C823071",
Name = "Epson Serial Interface Board with 32K Buffer - 1 x RS-232 Serial",
UPC = "C823071"
},
new Product()
{
Manufacturer = "Cisco Systems, Inc",
ManufacturerNumber = "WSX4013",
Name = "Cisco Catalyst 4000 Series Supervisor Engine II-Plus - 2 x GBIC, 1 x - Supervisor Engine",
UPC = "WSX4013"
}
}.ForEach(p => context.Products.Add(p));
}
private static void AddVendorProducts(UbidContext context)
{
Random random = new Random();
var vps = new List<VendorProduct>()
{
new VendorProduct()
{
ProductId = 1,
VendorId = 1,
Quantity = random.Next(3, 40),
SalesPrice = Converter.ConvertObjToDecimal(random.Next(20, 400)),
},
new VendorProduct()
{
ProductId = 2,
VendorId = 1,
Quantity = random.Next(3, 40),
SalesPrice = Converter.ConvertObjToDecimal(random.Next(20, 400)),
},
new VendorProduct()
{
ProductId = 3,
VendorId = 1,
Quantity = random.Next(3, 40),
SalesPrice = Converter.ConvertObjToDecimal(random.Next(20, 400)),
},
new VendorProduct()
{
ProductId = 4,
VendorId = 2,
Quantity = random.Next(3, 40),
SalesPrice = Converter.ConvertObjToDecimal(random.Next(20, 400)),
},
new VendorProduct()
{
ProductId = 4,
VendorId = 3,
Quantity = random.Next(3, 40),
SalesPrice = Converter.ConvertObjToDecimal(random.Next(20, 400)),
}
};
foreach (var vp in vps)
context.VendorProducts.Add(vp);
}
public class DropCreateIfChangeInitializer : DropCreateDatabaseIfModelChanges<UbidContext>
{
protected override void Seed(UbidContext context)
{
context.Seed(context);
base.Seed(context);
}
}
static UbidContext()
{
Database.SetInitializer<UbidContext>(new DropCreateIfChangeInitializer());
}
}
现在，发生的情况是，当它到达 VendorProducts 时，第一个添加得很好，但第二个不会保存，因为看起来 EF 没有设置 Vendor 对象，我看到的模式是如果 vendorid 和/或 productid 在同一上下文中的先前实体上使用，则对于添加的每个 vendorproduct，它不会填充供应商或产品，因此将其设置为 null。从我的代码中可以看出，我在下面明确设置了 VendorId，但是当 EF 将数据发送到数据库时，VendorId 为空。如果您需要更多信息，请告诉我。
谢谢
【问题讨论】：
-
嗯，问题：1）“第一个添加就好了，但是第二个不会保存”是什么意思？
SaveChanges是一个事务，要么什么都没有保存，要么什么都没有。您是否在SaveChanges中遇到异常，或者只是数据库中的第一个而其他人都丢失了？ 2）“但是当 EF 将数据发送到数据库时，VendorId 为空”：VendorId是int，它不能是null- 你到底是什么意思？
标签： c#-4.0 entity-framework-4 ef-code-first fluent-interface