c# DynamicObject class 来自循环的动态属性

Question

所以我创建了一个继承 DynamicObject

的 class

public class MyDynamicObject : DynamicObject{
private Dictionary<string, object> Fields = new Dictionary<string, object>();

public override bool TryGetMember(GetMemberBinder binder, out object result)
{
    return Fields.TryGetValue(binder.Name, out result);
}

public override bool TrySetMember(SetMemberBinder binder, object value)
{
    Fields[binder.Name] = value;
    return true;
}
}

并在此处称其为 class

public class Program
{
public static void Main()
{
    dynamic person = new MyDynamicObject();
    person.firstname = "Hello";
    Console.WriteLine(person.firstname);
 }
}

当然可以。但是我需要从

这样的字符串数组创建属性

string[] fields = new string[]{"taxid","newcol","addrs","gender"};
dynamic person = new MyDynamicObject();
foreach(var f in fields)
{
  person.f = "hello";
}

因此输出将是 person.taxi、person.newcol、person.addrs、person.gender

这可能吗？

Answer 1

以某种方式公开 Fields 字典，或者（更好）一种允许通过名称显式设置属性的方法。

请注意 ExpandoObject 已经这样做了，因为它可以转换为 IDictionary<string, object> 然后你

ExpandoObject eo = new ExpandoObject();
IDictionary<string, object> dict = eo;
dynamic d = eo;
dict["MyProperty"] = 42;
Console.WriteLine(d.MyProperty); // 42

如果你不能只使用ExpandoObject本身，你可以复制它的方法。

Answer 2

好的，根据@Jon Hanna 的建议，我想出了一个符合我要求的解决方案。我创建了一个接受名称的新 Add 方法。以下是我使用的更新代码。

public class DynamicFormData : DynamicObject
{
    private Dictionary<string, object> Fields = new Dictionary<string, object>();

    public int Count { get { return Fields.Keys.Count; } }

    public void Add(string name, string val = null)
    {
        if (!Fields.ContainsKey(name))
        {
            Fields.Add(name, val);
        }
        else
        {
            Fields[name] = val;
        }
    }

    public override bool TryGetMember(GetMemberBinder binder, out object result)
    {
        if (Fields.ContainsKey(binder.Name))
        {
            result = Fields[binder.Name];
            return true;
        }
        return base.TryGetMember(binder, out result); 
    }

    public override bool TrySetMember(SetMemberBinder binder, object value)
    {
        if (!Fields.ContainsKey(binder.Name))
        {
            Fields.Add(binder.Name, value);
        }
        else
        {
            Fields[binder.Name] = value;
        }
        return true;
    }

    public override bool TryInvokeMember(InvokeMemberBinder binder, object[] args, out object result)
    {
        if (Fields.ContainsKey(binder.Name) &&
            Fields[binder.Name] is Delegate)
        {
            Delegate del = Fields[binder.Name] as Delegate;
            result = del.DynamicInvoke(args);
            return true;
        }
        return base.TryInvokeMember(binder, args, out result);
    }
}

那我就这么叫吧

string[] fields = new string[]{"taxid","newcol","addrs","gender"};
dynamic formData = new DynamicFormData();

foreach(string field in fields)
{
    formData.Add(field, null);
}

c# DynamicObject class 来自循环的动态属性

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c#

dynamicobject