标签 Attribute

[AttributeUsage(AttributeTargets.All)]//指定Attribute的使用范围，比如只能在class级别使用
public class Column : Attribute
{
    public Column(string str)
    {
        this.str = str;
    }
    public string str { get; set; }
}
//第2个
[AttributeUsage(AttributeTargets.All)]
public class Table : Attribute
{
    public Table(string str)
    {
        this.str = str;
    }
    public string str { get; set; }
}

//2个属性
[Column("class")]
[Table("table class")]
public class Abc
{
    public string x { get; set; }
    [Column("attr")]
    public Int32 y { get; set; }
}
protected void Page_Load(object sender, EventArgs e)
{
    //通过反射可以调用到这个类型头上的attr
    Type type = typeof(Abc);
    bool isGot = Attribute.IsDefined(type, typeof(Column)); //查看有没有某个Attribute
    Attribute[] attrs = Attribute.GetCustomAttributes(type); //批量获取
    string xy =  attrs.First().GetType().Name; //可以查看它的名字来选择想要的，或是看有没有想要的.
    Column column = (Column)Attribute.GetCustomAttribute(type, typeof(Column)); //强转
    Column[] columns = (Column[])Attribute.GetCustomAttributes(type, typeof(Column));
    column = columns[0];
    string x = column.str; //调用方法或是公开属性等等都可以        

    //实例化之后也是可以一样拿
    Abc a = new Abc();
    PropertyInfo info = a.GetType().GetProperty("y"); 
    Column attribute2 = (Column)Attribute.GetCustomAttribute(info, typeof(Column));
    string xyz = attribute2.str;
}