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How can I use Generics to create a way of making an IEnumerable from an enum?

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遇见更好的自我
遇见更好的自我 2021-01-18 09:33

Given an enum like this:

public enum City {
    London    = 1,
    Liverpool  = 20,
    Leeds       = 25
}

public enum House {
    OneFloor    = 1,
    TwoF
3条回答
  • 一整个雨季
    一整个雨季 (楼主)
    2021-01-18 09:54

    Why not:

        IEnumerable GetValues()
    {
        return Enum.GetValues(typeof (T))
                   .Cast()
                   .Select(value => new {     
                                             value = Convert.ToInt32(value),
                                             name = value.ToString()
                                         });

    }



    So you can use:
    


    var result = GetValues();

    


    If you would like to make constraint generic T as enum, because enum cannot be used as generic contraint directly, but enum inherits from interface IConvertible, believe this way is okay:
    


    IEnumerable GetValues() where T: struct, IConvertible
{}



    To replace IEnumerable by Dictionary:
    


    Dictionary GetValues() where T :  struct, IConvertible
{
    return Enum.GetValues(typeof (T)).Cast()
               .ToDictionary(value => Convert.ToInt32(value),
                             value => value.ToString());
}

    


    Edit: As Magnus's comment, if you need to make sure the order of items, Dictionary is not the option. Define your own strong type would be better.
    
    
    
             
    
                                                        
    
            
            
    
              
                
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