编辑但不查看时如何实现IDataErrorInfo以对实体进行验证

Question

Using Entity Framework 6 with DB First but still relatively new to it. I am using IDataErrorInfo on the model for validation, which works fine when editing a single entity. Eg Editing a single Address.

However, I noticed a severe performance hit when loading multiple entities (using LINQ). (eg the command myContext.Address.ToList() when filling a datagridview was taking over a second to populate each row). This is because for every row retrieved from the DB, the corresponding entity fires the validation / error checking code multiple times. I realise this is the result of binding in the DataGridView , not due to simply retrieving from the DB.

I can work around this by setting a ValidationOn flag, set to false by default, that just returns true to all validation checks. That's much quicker but it still seems inefficient to run around those validation checks when there is no reason.

Is there a way I can disable the Interface so it can be manually 'activated' when needed?

I assume it would be better to derive a class from my Model Entities and use that for implementing IDataErrorInfo but how do I define a generic class that can derive from any of my context objects?

I have tried creating this:

public class ValidatingEntity : DbSet, IDataErrorInfo
    private readonly DbSet _myEntity;
    public ValidatingEntity(DbSet MyEntity) 
    {
        _myEntity = MyEntity
    }
}

which seems to work, but how do I know what the entity is to perform the correct validation tests. eg How would I do this:

public string this[string columnName]
{
    if (_myEntity is Address)
    {
        Address myAddress = (Address)_myEntity;
        If (columnName=="AddressCode")
        {
            If (myAddress.AddressCode == string.empty) return "Code can not be blank";
        }
    }
}

The code if (_myEntity is Address) gives the warning given expression is never of the provided (Address) type .

In summary,

• how to I create a derived class based on any of entities in my context?
• how would I instantiate that class from any one of my entities?
• is there a better way of doing this?

UPDATE 1

I believe I have solved this by creating a Common Base class and Deriving my entities from there using the instructions found here: Using A Common Base Class Across Entity Framework Database First Entities

It has also allowed me to build my own Interface to replace IDataErrorInfo as that as was causing my validation code to fire multiple times which I can now avoid.

Answer 1

经过测试后，我很高兴在更新1中确定的方法就是解决方案（即基于此： https : //fairwaytech.com/2013/09/using-a-common-base-class-across-entity-框架数据库先实体/