ef5 database first data annotation

问题

I am starting MVC4 with VS2012. I am also using EF5 with the "Database First" method of creating my classes.

However because the generated glasses can be regenerated I cannot put the Data Annotation details to assist with validation.

I have seen some code snippets that use MetaData and partial classes but I was wondering if anyone knows of a small compilable example that I can look at and pull apart to better understand how the vasious classes interlink.

Many many thanks for any help. Dave

回答1:

You can achieve what you need through extending models. Suppose that EF generated the following entity class for you:

namespace YourSolution
{
    using System;
    using System.Collections.Generic;

    public partial class News
    {
        public int ID { get; set; }
        public string Title { get; set; }                  
        public int UserID { get; set; }

        public virtual UserProfile User{ get; set; }
    }
}

and you want do some work arounds to preserve your you data annotations and attributes. So, follow these steps:

First, add two classes some where (wherever you want, but it's better to be in Models) like the following:

namespace YourSolution
{
    [MetadataType(typeof(NewsAttribs))]
    public partial class News
    {
         // leave it empty.
    }

    public class NewsAttribs
    {            
        // Your attribs will come here.
    }
}

then add what properties and attributes you want to the second class - NewsAttribs here. :

public class NewsAttrib
{
    [Display(Name = "News title")]
    [Required(ErrorMessage = "Please enter the news title.")]
    public string Title { get; set; }

    // and other properties you want...
}

Notes:

1) The namespace of the generated entity class and your classes must be the same - here YourSolution.

2) your first class must be partial and its name must be the same as EF generated class.

Go through this and your attribs never been lost again ...

来源：https://stackoverflow.com/questions/13224834/ef5-database-first-data-annotation

标签

entity-framework