用switch case处理一个很长的判断，例如56个民族01代表汉族，02代表藏族，03代表壮族...，当传入数字想获取民族名称时就得写56个case，当传入民族获取背后的数字时，又得再写56个case，如下所示：
private string GetNationValue(string s)
{
string result = "5";
switch (s)
{
case "01":
result = "汉族";
break;
case "02":
result = "藏族";
break;
case "03":
result = "壮族";
break;
case "04":
result = "朝鲜族";
break;
//这里省略其它......
}
return result;
}
private string GetNationKey(string s)
{
string result = "5";
switch (s)
{
case "汉族":
result = "01";
break;
case "藏族":
result = "02";
break;
case "壮族":
result = "03";
break;
case "朝鲜族":
result = "04";
break;
//这里省略其它......
}
return result;
}
这么长的代码很丑陋，要修改也不容易，可以通过Dictionary来改进，键和值是成对写在一起的，非常容易维护，改写后代码如下：
public enum FormatType
{
GetKey,
GetValue
}
public class Format
{
private static string Get(Dictionary<string, string> dict, FormatType formatType, string code)
{
if (formatType == FormatType.GetKey)
return dict.FirstOrDefault(d => d.Value == code).Key;
else
return dict.FirstOrDefault(d => d.Key == code).Value;
}
public static string GetNation(FormatType formatType, string code)
{
Dictionary<string, string> dict = new Dictionary<string, string>{
{"01","汉族"},
{"02","藏族"},
{"03","壮族"},
{"04","朝鲜族"}
//这里省略其它......
};
return Get(dict, formatType, code);
}
}
使用：
获取"汉族"的编码
string key = Format.GetNation(FormatType.GetKey, "汉族");
获取"01"代表的民族
string value = Format.GetNation(FormatType.GetValue, "01");