强制将静态类常量作为数据类型

Question

I have a static class with constants. I am looking for options to create a method which takes a dictionary as an argument and enforcing the key to be one of the constants from the static class.Here is my static class with constants.

Here is what I am trying to do

And here is what I am trying to enforce

Answer 1

From the sound of it, an Enum would be more suited to what you're trying to do.

public enum MyConstants
{
    FirstName,
    LastName,
    Title
}

public void CreateMe(Dictionary<MyConstants, string> propertyBag)
{
    ...
}

UPDATED

You could combine this with attributes to associate each enum with a specific string like so:

public enum PropertyNames
{
    [Description("first_name")]
    FirstName,
    [Description("last_name")]
    LastName,
    [Description("title")]
    Title
}

The value of each description attribute associated with each enum value could easily be grabbed via an extension method, like so:

public static class EnumExtensions
{
    public static string GetDescription(this Enum value)
    {
        FieldInfo fieldInfo = value.GetType().GetField(value.ToString());

        DescriptionAttribute[] attributes =
            (DescriptionAttribute[])fieldInfo.GetCustomAttributes(
            typeof(DescriptionAttribute),
            false);

        if (attributes != null &&
            attributes.Length > 0)
            return attributes[0].Description;
        else
            return value.ToString();
    }
}

Then in your "CreateMe"-method you can get the description and value of each dictionary entry by doing something similar to this:

void CreateMe(Dictionary<PropertyNames, string> propertyBag)
{
    foreach (var propertyPair in propertyBag)
    {
        string propertyName = propertyPair.Key.GetDescription();
        string propertyValue = propertyPair.Value;
    }
} 

Answer 2

Even though this has been already answered, there is another approach, like so:

public class MyOwnEnum
{
    public string Value { get; private set; }

    private MyOwnEnum(string value)
    {
        Value = value;
    }

    public static readonly MyOwnEnum FirstName = new MyOwnEnum("Firstname");
    public static readonly MyOwnEnum LastName = new MyOwnEnum("LastName");
}

It behaves same way like Enum and can be used in your code with same syntax. I cannot give credit to whoever came up with it, but I believe I came upon it when searching for Enums with multiple values.

Answer 3

With strings you can't enforce fact that keys come from limited set of vialues compile time.

Use enum or custom class (possibly with implicit conversion to string) instead.