不确定我是否正确获取了"描述"属性

Question

我有一个单独的类，我想获得"Description"属性:

public class Fruits
{
    [Description("The green apples are very green.")]  
    public const string Apples= "Green";
    [Description("Sunkist oranges are very sweet.")]  
    public const string Oranges= "Sunkist";
    [Description("Red grapes are make for wine.")]  
    public const string Grapes= "Red";
}

出于参数的考虑，我有一个单独的类，我想检索Description。这段代码看起来像:

        Type fruitType = typeof(LotsOfFruits.Fruits);
        FieldInfo[] fields = fruitType.GetFields();
        foreach (var field in fields)
        {
            Console.WriteLine("Name: {0}", field.Name);
            Console.WriteLine("Value: {0}", field.GetRawConstantValue().ToString());
            List<System.Attribute> attr = field.GetCustomAttributes(typeof(System.ComponentModel.DescriptionAttribute)).ToList();
        }

名称和值字段正在正确提取。我在获取Description属性时遇到了困难。在这一点上，我想知道这是否是正确的方法(即把它放在一个列表中)。

对于获取description属性有什么建议吗?

Answer 1

我不知道你的上下文，但通过阅读你的代码，似乎你会更好的子类化类水果与名称和描述属性:

public abstract class Fruit
{
    public abstract string Name { get; }
    public abstract string Description { get; }
}
public class Apple : Fruit
{
    public string Name { get { return "Apple"; }
    public string Description { get { return "The green apples are very green."; }
}
public class Orange : Fruit
{
    public string Name { get { return "Orange"; }
    public string Description { get { return "Sunkist oranges are very sweet."; }
}

除此之外，你的代码似乎是正确的

Answer 2

你拥有的很好;你只需要:

var attr = (DescriptionAttribute)field.GetCustomAttribute(
    typeof(DescriptionAttribute));
if(attr != null) Console.WriteLine("Desc: {0}", attr.Description);

或者在以后的。net版本中:

var attr = field.GetCustomAttribute<DescriptionAttribute>();
if(attr != null) Console.WriteLine("Desc: {0}", attr.Description);

Answer 3

这对我来说是有效的，但是您需要强制转换DescriptionAttribute，因为它是一个基属性类。此外，我倾向于获得第一个或默认值，除非我知道我可能有多个。

class Program
{
    static void Main(string[] args)
    {
        Type fruitType = typeof(Fruits);
        FieldInfo[] fields = fruitType.GetFields();
        foreach (var field in fields)
        {
            Console.WriteLine("Name: {0}", field.Name);
            Console.WriteLine("Value: {0}", field.GetRawConstantValue().ToString());
            var attr = field.GetCustomAttributes(typeof(System.ComponentModel.DescriptionAttribute)).Cast < System.ComponentModel.DescriptionAttribute>().FirstOrDefault();
            Console.WriteLine("Description: {0}", attr.Description);
            Console.ReadLine();
        }
    }
}
public class Fruits
{
    [Description("The green apples are very green.")]  
    public const string Apples= "Green";
    [Description("Sunkist oranges are very sweet.")]  
    public const string Oranges= "Sunkist";
    [Description("Red grapes are make for wine.")]  
    public const string Grapes= "Red";
}