适当的c＃集合，可通过multy键快速搜索

Posted 2021-05-06

您好我正在努力重构一些遗留代码。有些代码表示从自定义类型到c＃类型的“转换器”。

          ...
           if (dataType == CustomType.Bit)
            {
                return typeof(bool);
            }
            else if (dataType == CustomType.Bittype ||
                dataType == CustomType.Char ||
                dataType == CustomType.Fromtotype ||
                dataType == CustomType.Mdcintervaltype ||
                dataType == CustomType.Nclob ||
                dataType == CustomType.Nchar ||
                dataType == CustomType.Ntext ||
                dataType == CustomType.Nvarchar ||
                dataType == CustomType.Nvarchar2 ||
                dataType == CustomType.Varchar ||
                dataType == CustomType.Varchar2)
            {
                return typeof(string);
            }
            else if (dataType == CustomType.Date ||
                dataType == CustomType.Datetime ||
                dataType == CustomType.Timestamp3 ||
                dataType == CustomType.Timestamp6)
            {
                return typeof(DateTime);
            }
            else if (dataType == CustomType.Decimal ||
                dataType == CustomType.Money ||
                dataType == CustomType.Number ||
                dataType == CustomType.Numeric)
            {
                return typeof(decimal);
            }

...

问：我正在寻找能够帮助我快速搜索一对多关系的C＃结构（无论是否收集）。 （即我希望看起来像{收集可能的密钥} ==> {value}

P.s我认为每个Custromtype都是键并且返回相同类型的简单字典不是“美丽的”

new Dictionary<string, Type>()(){
    { CustomType.Bittype, typeof(string)},
    { CustomType.Fromtotype, typeof(string)}
     ...
    { CustomType.Datetime,  typeof(DateTime)},
    { CustomType.Date, typeof(DateTime)}
    ....
}

答案

如果你把Dictionary作为默认类型，你可以使string更美丽;另一个建议是将其作为一种扩展方法来实现

 public static class CustomTypeExtensions {
   private static Dictionary<CustomType, Type> s_Map = new Dictionary<CustomType, Type>() {
     {CustomType.Datetime,  typeof(DateTime)},
     {CustomType.Date, typeof(DateTime}, 
     ...
   }; 

   public static Type ToType(this CustomType value) {
     if (s_Map.TryGetValue(value, out var result))
       return result;
     else
       return typeof(string); // when not found, return string 
   }
 }

....

var custom = CustomType.Bittype;

...

Type t = custom.ToType();   

另一答案

德米特里的方法很好，你也可以使用这样的东西：

class Example
{
    private readonly HashSet<CustomType> _stringCompatibleTypes = new HashSet<CustomType>
    {
        CustomType.Char, CustomType.Fromtotype, CustomType.Nclob, ...
    };

    private readonly HashSet<CustomType> _dateCompatibleTypes = new HashSet<CustomType>
    {
        CustomType.Datetime, CustomType.Timestamp3, CustomType.Timestamp6, ...
    };

    // Another type sets

    public Type Foo(CustomType dataType)
    {
        if (_stringCompatibleTypes.Contains(dataType))
        {
            return typeof(string);
        }

        if (_dateCompatibleTypes.Contains(dataType))
        {
            return typeof(DateTime);
        }

        ...
    }
}