添加数据注释到实体框架（或Linq to SQL）生成的类 [英] Add Data Annotation To Entity Framework(Or Linq to SQL) generated class

问题描述

可以添加更多数据安抚成员，如 Range ，必需，...到实体框架或 Linq to SQL 自动生成的类

Is it possible to add more Data Anootation member such as Range,Required,... to Entity Framework or Linq to SQL generated classes automatically ?

我想为我的课程使用数据注释验证

I want to use data annotation validation for my classes

谢谢

编辑1）

我为Northwind数据库创建一个实体框架模型并添加Product class.a部分代码如下：

I create an entity framework model for Northwind database and add Product class.a part of code is like this:

[EdmEntityTypeAttribute(NamespaceName="NorthwindModel", Name="Product")]
[Serializable()]
[DataContractAttribute(IsReference=true)]
public partial class Product : EntityObject
{
    #region Factory Method

    /// <summary>
    /// Create a new Product object.
    /// </summary>
    /// <param name="productID">Initial value of the ProductID property.</param>
    /// <param name="productName">Initial value of the ProductName property.</param>
    /// <param name="discontinued">Initial value of the Discontinued property.</param>
    public static Product CreateProduct(global::System.Int32 productID, global::System.String productName, global::System.Boolean discontinued)
    {
        Product product = new Product();
        product.ProductID = productID;
        product.ProductName = productName;
        product.Discontinued = discontinued;
        return product;
    }

    #endregion
    #region Primitive Properties

    /// <summary>
    /// No Metadata Documentation available.
    /// </summary>
    [EdmScalarPropertyAttribute(EntityKeyProperty=true, IsNullable=false)]
    [DataMemberAttribute()]
    public global::System.Int32 ProductID
    {
        get
        {
            return _ProductID;
        }
        set
        {
            if (_ProductID != value)
            {
                OnProductIDChanging(value);
                ReportPropertyChanging("ProductID");
                _ProductID = StructuralObject.SetValidValue(value);
                ReportPropertyChanged("ProductID");
                OnProductIDChanged();
            }
        }
    }
    private global::System.Int32 _ProductID;
    partial void OnProductIDChanging(global::System.Int32 value);
    partial void OnProductIDChanged();

我希望ProductID是必需的，但我无法以这种方式编写代码：

I want ProductID being Required but I can't write code this way:

public partial class Product 
    {
        [Required(ErrorMessage="nima")]
        public global::System.Int32 ProductID;

    }

推荐答案

是的。您需要为每个实体创建第二个部分类，并将其链接到具有替代属性的辅助类。

Yes. You need to create a 2nd partial class for each entity and link it to an auxiliary class with substitute properties.

假设你有一个生成的部分类Customer {public string Name {get;组; }}

生成的类始终被标记为partial。

Suppose you have a generated partial class Customer { public string Name { get; set; } }
The generated class will always be marked as partial.

然后，您需要添加一个文件：

Then you need to add a file with :

[MetadataType(typeof(CustomerMetadata))]
public partial class Customer
{
    // it's possible to add logic and non-mapped properties here
}


public class CustomerMetadata
{
    [Required(ErrorMessage="Name is required")] 
    public object Name { get; set; }   // note the 'object' type, can be anything
}

不要认为这是一个非常优雅的解决方案，但它的作品。

Personally I don't consider this a very elegant solution but it works.

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