数据注解特性--StringLength

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StringLength attribute can be applied to a string type property of a class. EF Code-First will set the size of a column as specified in StringLength attribute. Note that it can also be used with ASP.Net MVC as a validation attribute.

Consider the following example.

using System.ComponentModel.DataAnnotations;

public class Student
{
    public Student()
    { 
        
    }
    public int StudentID { get; set; }
     
    [StringLength(50)]
    public string StudentName { get; set; }
        
}
        

As you can see in the above code, we have applied StringLength attribute to StudentName. So, Code-First will create a nvarchar(50) column StudentName in the Student table as shown below.

Entity Framework also validates the value of a property for StringLength attribute if you set the value more than the specified size. For example, if you set more than 50 chars long StudentName then EF will throw EntityValidationError.

数据注解特性--StringLength

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原文地址：http://www.cnblogs.com/caofangsheng/p/5023835.html