从属性值

Question

有了这个简单的类获取属性：

public class Book 
{ 
    [DataMember] 
    [Column("Bok_Name")] 
    [Author("AuthorName")] 
    public string Name{ get; set; } 

    [DataMember] 
    [Column("Bok_Publisher")] 
    public string Publisher{ get; set; } 
} 

如何，我可以从一个属性知道该属性的类型是列和值Bok_Name获得的PropertyInfo。我试图用linq查询来做到这一点。

Answer 1

使用反射和.NET扩展CustomAttributeExtensions.GetCustomAttribute{T}方法，您可以找到具有自定义属性的属性。在这种情况下，自定义属性来自System.ComponentModel.DataAnnotations.Schema.ColumnAttribute。

var book = new Book { Name = "Jitterbug Perfume" }; 

PropertyInfo bokName = typeof(Book) 
    .GetProperties(BindingFlags.Public | BindingFlags.Instance) // add other bindings if needed 
    .FirstOrDefault(x => x.GetCustomAttribute<ColumnAttribute>() != null 
     && x.GetCustomAttribute<ColumnAttribute>().Name.Equals("Bok_Name", StringComparison.OrdinalIgnoreCase)); 

// the above query only gets the first property with Column attribute equal to "Bok_Name" 
// if there are more than one, then use a .Where clause instead of FirstOrDefault. 
if (bokName != null) 
{ 
    string name = bokName.GetValue(book).ToString(); 
    // do other stuff 
} 

Answer 2

var type = typeof (Book); //or var type=instance.GetType(); 

    var res=type.GetProperties(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic) 
     .Where(
      p => 
       (p.GetCustomAttribute<ColumnAttribute>() ?? new ColumnAttribute()).Value == "Bok_Name");