类型和字典列表的替代

Question

Ideally this is what I want to do.

  private List<Type,Dictionary<string,string>> dynamicFields;

example of this would be.

  Class1      "1","value"
              "2","value1"

Why i want this for, is I will add in one go Type and some dictionary fields for each and then use linq later to retrieve those belonging to each class for some other operation.

Since this is not possible as compiler will give me error.

"using the Generic type List requires one argument"

What could be the approach to create kind of object I want to.

Answer 1

The simplest answer would be to use dictionary of a dictionary:

private Dictionary<Type, Dictionary<string, string>> dynamicFields;

Note you do need to make sure you initialize each outer entry with a Dictionary<string, string> before adding entries, and to get an inner entry you would need to make two calls to TryGetValue . As you describe it you are nesting containers, and passing the inner dictionary to another method, so this may indeed be the best option.

---

Hopefully there is only one Dictionary<string, string> for each Type . If not, and you cannot merge them, you would now need a list and things get one more step uglier:

private Dictionary<Type, List<Dictionary<string, string>>> dynamicFields;

However this would still arguably be the most efficient way of retrieving the list of inner dictionaries given a certain Type .

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Now, you were looking for an alternative. I am not sure if this applies in your particular case, but it sounds like you're trying to create a set of property bags, what I might want to call a static extension property. I would question whether you truly want the property bags to be static, or if they would instead belong to an instance of Class1 et al. In this case I would recommend instead to have your classes inherit from a base class which contains an extensible property bag. ExpandoObject basically already does this, but you could implement something yourself if you explicitly wanted a dictionary of strings. For example:

abstract class DynamicFieldEntity
{
    protected Dictionary<string, string> DynamicFields { get; } = 
        new Dictionary<string, string>();
}

class Class1 : DynamicFieldEntity {}

Answer 2

Because List accepts just one argument as generic parameter. You must declare a class A like this:

public class A
{
     public Type Type { get; set; }
     public Dictionary<string, string> KeyValue { get; set; }
}

and then declare list as private List<A> dynamicFields