c# - Dynamically Flat C# object class 运行时的属性列表

Question

我有一个这样的 A 类:

public class A
{
    private String id;              // Generated on server
    private DateTime timestamp;
    private int trash;
    private Humanity.FeedTypeEnum feedType
    private List<Property> properties;
// ...

哪里Property是:

public class Property
{
    private Humanity.PropertyTypeEnum type;
    private string key;
    private object value;
//...

我想构建一个扁平的动态对象 List<Property> properties A 的字段到原始属性。例如:

A a = new A();
a.Id = "Id";
a.Timestamp = DateTime.Now;
a.Trash = 2;
a.FeedType = Humanity.FeedTypeEnum.Mail;
a.Properties = new List<Property>()
{
    new Property()
    {
        Type = Humanity.PropertyTypeEnum.String,
        Key = "name"
        Value = "file1.pdf"
    },
    new Property()
    {
        Type = Humanity.PropertyTypeEnum.Timestamp,
        Key = "creationDate",
        Value = Datetime.Now
    }
}

正如我评论过的，我想把这个 a 弄平对象以便访问属性:

String name = a.Name;
DateTime creationDate = a.CreationDate;
a.Name = "otherName";
a.CreationDate = creationDate.AddDays(1);

我已经使用反射实现了这一点。但是，我发现这是使用 ExpandoObject 的最佳选择。 .

问题是，我如何使用 ExpandoObject 来做到这一点？类(class)？

Answer 1

您可以扩展DynamicObject 类做您想做的事情:

class A : System.Dynamic.DynamicObject
{
    // Other members
    public List<Property> properties;

    private readonly Dictionary<string, object> _membersDict = new Dictionary<string, object>();

    public override bool TryGetMember(System.Dynamic.GetMemberBinder binder, out object result)
    {
        result = null;
        if (!_membersDict.ContainsKey(binder.Name))
            return false;

        result = _membersDict[binder.Name];
        return true;
    }

    public override bool TrySetMember(System.Dynamic.SetMemberBinder binder, object value)
    {
        if (!_membersDict.ContainsKey(binder.Name))
            return false;

        _membersDict[binder.Name] = value;
        return true;
    }

    public void CreateProperties()
    {
        foreach (Property prop in properties)
        {
            if (!_membersDict.ContainsKey(prop.key))
            {
                _membersDict.Add(prop.key, prop.value);
            }
        }
    }
}

然后像这样使用它:

A a = new A();
/////////
a.Properties = new List<Property>()
{
    new Property()
    {
        Type = Humanity.PropertyTypeEnum.String, // Now this property is useless, the value field has already a type, if you want you can add some logic around with this property to ensure that value will always be the same type
        Key = "name"
        Value = "file1.pdf"
    },
    new Property()
    {
        Type = Humanity.PropertyTypeEnum.Timestamp,
        Key = "creationDate",
        Value = Datetime.Now
    }
}
a.CreateProperties();
dynamic dynA = a;
dynA.name = "value1";