asp.net-mvc-3 – 在MVC3中使用强类型视图时可能的模型继承？

首先,创建一个自定义属性来装饰基类的每个属性.这是我们的自定义提供程序的标志所必需的,以指示何时需要进一步分析.这是属性：

[AttributeUsage(AttributeTargets.All,Inherited = true,AllowMultiple = true)]
public class BaseTypeAttribute : Attribute { }

接下来,创建一个继承自DataAnnotationsModelMetadataProvider的自定义ModelMetadataProvider：

public class MyModelMetadataProvider : DataAnnotationsModelMetadataProvider
{
    protected override ModelMetadata CreateMetadata(
        IEnumerable<Attribute> attributes,Type containerType,Func<object> modelAccessor,Type modelType,string propertyName)
    {
        var attribute = attributes.FirstOrDefault(a => a.GetType().Equals(typeof(BaseTypeAttribute))) as BaseTypeAttribute;
        if (attribute != null && modelAccessor != null)
        {
            var target = modelAccessor.Target;
            var containerField = target.GetType().GetField("container");
            if (containerField == null)
            {
                var vdi = target.GetType().GetField("vdi").GetValue(target) as ViewDataInfo;
                var concreteType = vdi.Container.GetType();
                return base.CreateMetadata(attributes,concreteType,modelAccessor,modelType,propertyName);
            }
            else
            {
                var container = containerField.GetValue(target);
                var concreteType = container.GetType();
                var propertyField = target.GetType().GetField("property");
                if (propertyField == null)
                {
                    concreteType = base.GetMetadataForProperties(container,containerType)
                        .FirstOrDefault(p => p.PropertyName == "ConcreteType").Model as System.Type;
                    if (concreteType != null)
                        return base.GetMetadataForProperties(container,concreteType)
                            .FirstOrDefault(pr => pr.PropertyName == propertyName);
                }
                return base.CreateMetadata(attributes,propertyName);
            }
        }
        return base.CreateMetadata(attributes,containerType,propertyName);
    }
}

然后,创建一个继承自DataAnnotationsModelValidatorProvider的自定义ModelValidatorProvider：

public class MyModelMetadataValidatorProvider : DataAnnotationsModelValidatorProvider
{
    protected override IEnumerable<ModelValidator> GetValidators(ModelMetadata metadata,ControllerContext context,IEnumerable<Attribute> attributes)
    {
        List<ModelValidator> vals = base.GetValidators(metadata,context,attributes).ToList();

        var baseTypeAttribute = attributes.FirstOrDefault(a => a.GetType().Equals(typeof(BaseTypeAttribute))) 
            as BaseTypeAttribute;

        if (baseTypeAttribute != null)
        {
            // get our parent model
            var parentMetaData = ModelMetadataProviders.Current.GetMetadataForProperties(context.Controller.ViewData.Model,metadata.ContainerType);

            // get the concrete type
            var concreteType = parentMetaData.FirstOrDefault(p => p.PropertyName == "ConcreteType").Model;
            if (concreteType != null)
            {
                var concreteMetadata = ModelMetadataProviders.Current.GetMetadataForProperties(context.Controller.ViewData.Model,Type.GetType(concreteType.ToString()));

                var concretePropertyMetadata = concreteMetadata.FirstOrDefault(p => p.PropertyName == metadata.PropertyName);

                vals = base.GetValidators(concretePropertyMetadata,attributes).ToList();
            }
        }
        return vals.AsEnumerable();
    }
}

之后,在Global.asax.cs中的Application_Start中注册两个自定义提供程序：

ModelValidatorProviders.Providers.Clear();
ModelValidatorProviders.Providers.Add(new MvcApplication8.Controllers.MyModelMetadataValidatorProvider());
ModelMetadataProviders.Current = new MvcApplication8.Controllers.MyModelMetadataProvider();

现在,改变你的模型：

public class Person
{
    public Type ConcreteType { get; set; }

    [Required]
    [Display(Name = "Full name")]
    [BaseType]
    public string FullName { get; set; }

    [Display(Name = "Address Line 1")]
    [BaseType]
    public virtual string Address1 { get; set; }
}

public class Sender : Person
{
    public Sender()
    {
        this.ConcreteType = typeof(Sender);
    }

    [Required]
    [Display(Name = "Address Line One")]
    public override string Address1 { get; set; }
}

public class Receiver : Person
{
}

请注意,基类具有新属性ConcreteType.这将用于指示哪个继承类已实例化此基类.每当继承类具有覆盖基类中元数据的元数据时,继承类的构造函数应该设置基类ConcreteType属性.

现在,即使您的视图使用基类,特定于任何具体继承类的属性也将出现在视图中,并将影响模型的验证.

此外,您应该能够将View转换为Person类型的模板,并将该模板用于使用基类的任何实例或从中继承.