反思帮助。根据其属性从一个类中创建一个集合？

Question

我需要一点帮助。我对反思还很陌生。我们正在使用第 3 方 api，它返回一个名为“AddressList”的类。它内部有公共属性，字面上称为 Address1、Address1Name、Address1Desc、Address2、Address2Name、Address2Desc、Address3、Address3Name、Address3Desc、... Address99、Address99Name、Address99Desc.. 还有一些其他属性。我有一个名为“SimpleAddress”的类，它只有 3 个属性（地址、名称、描述）。我想要做的是当我得到“AddressList”类返回时，我想通过AddressDesc99循环AddressDesc1 ...并且无论哪个不为null或为空，我想创建一个“SimpleAddress”实例，填充它的属性，并将其添加到列表中...有人可以指出我正确的方向吗？显然，如果“AddressList”是某种集合，这会更好，但不幸的是它不是。它是从大型机的返回字符串生成的。

感谢您的帮助， ~ck 在圣地亚哥

Answer 1

咳咳。你可以这样做：

List<SimpleAddress> addresses = new List<SimpleAddress>();

string addressPropertyPattern = "Address{0}";
string namePropertyPattern = "Address{0}Name";
string descPropertyPattern = "Address{0}Desc";

for(int i = 1; i <= MAX_ADDRESS_NUMBER; i++)
{
    System.Reflection.PropertyInfo addressProperty = typeof(AddressList).GetProperty(string.Format(addressPropertyPattern, i));
    System.Reflection.PropertyInfo nameProperty = typeof(AddressList).GetProperty(string.Format(namePropertyPattern, i));
    System.Reflection.PropertyInfo descProperty = typeof(AddressList).GetProperty(string.Format(descPropertyPattern, i));

    SimpleAddress address = new SimpleAddress();

    address.Address = (string)addressProperty.GetValue(yourAddressListObject, null);
    address.Name = (string)nameProperty.GetValue(yourAddressListObject, null);
    address.Description = (string)descProperty.GetValue(yourAddressListObject, null);

    addresses.Add(address);
}

Answer 2

首先获取相关类的类型并调用 GetProperties 方法。

PropertyInfo[] properties = myMainframeObject.GetType().GetProperties();

每个 PropertyInfo 都有一个 Name 属性（一个字符串），您可以使用它来匹配。循环遍历所有属性，并编写创建 SimpleAddress 新实例的代码。

在这个循环中，您可以访问您的大型机对象并提取您需要的属性值：

// imagine that in this case, 'p' is a PropertyInfo that represents Address2Name
var simpleAddress = new SimpleAddress();
simpleAddress.Name = p.GetValue(myMainframeObject, null);

（null 永远不会用于普通属性 - 它旨在与索引属性一起使用）。

Answer 3

您应该能够执行以下操作：

List<SimpleAddress> CreateList(AddressList address)
{
    List<SimpleAddress> values = new List<SimpleAddress>();
    Type type = address.GetType();
    for (int i=1;i<=99;++i)
    {
         string address = type.GetProperty("Address" + i.ToString()).GetValue(address,null).ToString();
         string addressDesc = type.GetProperty("Address" + i.ToString() + "Desc").GetValue(address,null).ToString();
         string addressName = type.GetProperty("Address" + i.ToString() + "Name").GetValue(address,null).ToString();


         if (!string.IsNullOrEmpty(addressDesc) || !string.IsNullOrEmpty(addressName) || !string.IsNullOrEmpty(address)  )
              value.Add(new SimpleAddress(address,addressDesc,addressName));
    }

    return values;
 }

Answer 4

未经测试（原因很明显），但类似：

List<SimpleAddress> newList = new List<SimpleAddress>();
AddressList list = ...
Type type = list.GetType();
PropertyInfo prop1, prop2, prop3;
int index = 1;
while((prop1 = type.GetProperty("Address" + index)) != null
   && (prop2 = type.GetProperty("Address" + index + "Name")) != null
   && (prop3 = type.GetProperty("Address" + index + "Desc")) != null) {
    string addr = (string) prop1.GetValue(list, null),
           name = (string) prop2.GetValue(list, null),
           desc = (string) prop3.GetValue(list, null);

    if(addr == null || name == null || desc == null) {
       continue; // skip but continue
    }

    SimpleAddress newAddr = new SimpleAddress(addr, name, desc);
    newList.Add(newAddr);
    index++;
}

Answer 5

如果你想使用 linq

public static class MyTools
{
    public static TReturn GetValue<TReturn>(this object input, 
                                            string propertyName)
    {
        if (input == null)
            return default(TReturn);
        var pi = input.GetType().GetProperty(propertyName);
        if (pi == null)
            return default(TReturn);
        var val = pi.GetValue(input, null);
        return (TReturn)(val == null ? default(TReturn) : val);
    }

    public static string GetString(this object input, string propertyName)
    {
        return input.GetValue<string>(propertyName);
    }

    public static List<SimpleAddress> GetAddress(this MyObject input)
    {
        return (
            from i in Enumerable.Range(1, 2)
            let address = input.GetString("Address" + i.ToString())
            let name = input.GetString("Address" + i.ToString() + "Name")
            let desc = input.GetString("Address" + i.ToString() + "Desc")
            select new SimpleAddress() { Address = address, 
                                         Name = name, 
                                         Description = desc }
           ).ToList();
    }
}

Answer 6

var addrList = new AddressList
{
    Address1Name = "ABC",
    Address1Desc = "DEF",
    Address1 = "GHI",
    Address3Name = "X",
    Address3Desc = "Y",
    Address3 = "Z"
};

var addresses =
        from i in Enumerable.Range(1, 99)
        let desc = typeof(AddressList).GetProperty(string.Format("Address{0}Desc", i)).GetValue(addrList, null) as string
        let name = typeof(AddressList).GetProperty(string.Format("Address{0}Name", i)).GetValue(addrList, null) as string
        let address = typeof(AddressList).GetProperty(string.Format("Address{0}", i)).GetValue(addrList, null) as string
        where !string.IsNullOrEmpty(address)
        select new SimpleAddress
        {
            Name = name,
            Description = desc,
            Address = address
        };