LINQ表达式无法翻译，当我尝试筛选我的值对象属性时。

huangapple
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英文:

The LINQ expression could not be translated when I try filter my value object property

问题

我在过滤我的查询时遇到了一个问题。这是我的查询：

  1.  var products = _context.Products.Select(x => new GetProductsDto { 
  2.                 Id = x.Id,
  3.                 Name = x.Name.Value,
  4.                 Quantity = x.Quantity.Value,
  5.                 Brand = x.Brand,
  6.                 Displayed = x.Displayed,
  7.                 Price = x.Price,
  8.                 Category = x.Category.Name.Value
  9.             });
  11. products = products.Where(p => p.Name.Contains(request.SearchKey));

这是我的产品实体：

  1. public class Product {
  2.         public Name Name { get; private set; }
  3.         public Quantity Quantity { get; private set; }
  4.         public string Brand { get; private set; }
  5.         public string Description { get; private set; }
  6.         public int Price { get; private set; }
  7.         public bool Displayed { get; private set; }
  8.         public int CategoryId { get; set; }
  9.         public virtual Category Category { get; set; }
  10.         public virtual ICollection<ProductImage> ProductImages { get; private set; }
  11.         public virtual ICollection<ProductFeature> ProductFeatures { get; private set; }
  12. }

这是我的Name值对象：

  1. public class Name : ValueObject
  2.     {
  3.         public const byte MaxLen = 100;
  4.         public string Value { get; private set; }
  6.         private Name()
  7.         {
  8.         }
  10.         public static Name Create(string name)
  11.         {
  12.             var shopName = new Name();
  13.             if (name.Length > MaxLen)
  14.             {
  15.                 shopName.Result.WithError(
  16.                     string.Format(Validations.MaxLenValidation, DataDictionary.ShopName, MaxLen));
  17.                 return shopName;
  18.             }
  19.             shopName.Value = name;
  20.             return shopName;
  21.         }
  22.     }

这是我映射到数据库的产品实体：

  1. internal class ProductEntityMap : IEntityTypeConfiguration<Product>
  2.     {
  3.         public void Configure(EntityTypeBuilder<Product> builder)
  4.         {
  5.             builder.HasKey(x => x.Id);
  7.             builder.Property(x => x.Id)
  8.                 .ValueGeneratedOnAdd();
  10.             builder.Property(x => x.Quantity)
  11.                 .HasConversion(x => x.Value, 
  12.                     x => Domain.Aggregates.Products.ValueObjects.Quantity.Create(x));
  14.             builder.Property(x => x.Name)
  15.                 .HasConversion(x => x.Value,
  16.                     x => Domain.SharedKernel.Name.Create(x));
  17.         }
  18.     }

我认为错误是因为在我的实体中使用了'Name'值对象。请帮助我。

英文:

I encountered an issue when filtering my Query. this is my query:

  1.  var products = _context.Products.Select(x =&gt; new GetProductsDto { 
  2.                 Id = x.Id,
  3.                 Name = x.Name.Value,
  4.                 Quantity = x.Quantity.Value,
  5.                 Brand = x.Brand,
  6.                 Displayed = x.Displayed,
  7.                 Price = x.Price,
  8.                 Category = x.Category.Name.Value
  9.             });
  11. products = products.Where(p =&gt; p.Name.Contains(request.SearchKey));

And This is my Product Entity:

  1. public class Product{
  2.         public Name Name { get; private set; }
  3.         public Quantity Quantity { get; private set; }
  4.         public string Brand { get; private set; }
  5.         public string Description { get; private set; }
  6.         public int Price { get; private set; }
  7.         public bool Displayed { get; private set; }
  8.         public int CategoryId { get; set; }
  9.         public virtual Category Category { get; set; }
  10.         public virtual ICollection&lt;ProductImage&gt; ProductImages { get; private set; }
  11.         public virtual ICollection&lt;ProductFeature&gt; ProductFeatures { get; private set; }
  12. }

And This My Name ValueObject:

  1. public class Name : ValueObject
  2.     {
  3.         public const byte MaxLen = 100;
  4.         public string Value { get; private set; }
  6.         private Name()
  7.         {
  8.         }
  10.         public static Name Create(string name)
  11.         {
  12.             var shopName = new Name();
  13.             if (name.Length &gt; MaxLen)
  14.             {
  15.                 shopName.Result.WithError(
  16.                     string.Format(Validations.MaxLenValidation, DataDictionary.ShopName, MaxLen));
  17.                 return shopName;
  18.             }
  19.             shopName.Value = name;
  20.             return shopName;
  21.         }
  22.     }

And This Is My Product Entity Map to Data Base:

  1. internal class ProductEntityMap : IEntityTypeConfiguration&lt;Product&gt;
  2.     {
  3.         public void Configure(EntityTypeBuilder&lt;Product&gt; builder)
  4.         {
  5.             builder.HasKey( x =&gt; x.Id);
  7.             builder.Property(x =&gt; x.Id)
  8.                 .ValueGeneratedOnAdd();
  10.             builder.Property(x =&gt; x.Quantity)
  11.                 .HasConversion(x =&gt; x.Value, 
  12.                     x =&gt; Domain.Aggregates.Products.ValueObjects.Quantity.Create(x));
  14.             builder.Property(x =&gt; x.Name)
  15.                 .HasConversion(x =&gt; x.Value,
  16.                     x =&gt; Domain.SharedKernel.Name.Create(x));
  17.         }
  18.     }

I think the error is because I'm using 'Name' valueObject In my entity. please help me

答案1

得分: 0

最后我找到了解决方案。我在我的ValueObject类中添加了这行代码，例如在我的Name ValueObject类中，代码如下：

  1. public static explicit operator string(Name name) => name.Value;

然后我修改了我的查询，如下所示：

  1. var shops = _context.Shops.AsQueryable();            
  2. if (searchKey is not null)
  3.     shops = shops
  4.         .Where(x => ((string)x.Name).ToLower().Contains(searchKey.ToLower()));

最后，我检查了SQL Server Profiler工具，以确保查询在服务器上执行而不是在客户端上。

英文:

Finally I found the solution. I added this line to my ValueObject class, for example in my Name ValueObject class it's like this:

  1. public static explicit operator string(Name name) =&gt; name.Value;

And I changed my query like below:

  1. var shops = _context.Shops.AsQueryable();            
  2. if (searchKey is not null)
  3.     shops = shops
  4.         .Where(x =&gt; ((string)x.Name).ToLower().Contains(searchKey.ToLower()));

And at the end, I checked the SQL Server Profiler Tools to be sure that query execute in server not in client.

huangapple
  • 本文由 发表于 2023年7月20日 20:36:06
  • 转载请务必保留本文链接：https://go.coder-hub.com/76729953.html
  • domain-driven-design
  • entity-framework-core
  • linq
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