NPinyin does not support Chinese-English mixed conversion, how to break it

Recently, the requirement of using Chinese characters to pinyin in the project is realized by NPinyin, but in the process of using it, there is a situation that does not meet the expectations.

Let's take a look at normal use first:

 string str = NPinyin.Pinyin.GetPinyin("小黄本黄");
Console.WriteLine(str);

The output is

xiao huang ben huang

Obviously, this is expected, but if we don't know whether the current string is Chinese or Pinyin before calling this conversion method, do we expect that the Pinyin part will not be changed? But not actually:

 string str = NPinyin.Pinyin.GetPinyin("xiao huang ben huang");
Console.WriteLine(str);

The output is

xiaohuangbenhuang

It also converts each English character, resulting in an extra space after each character.

If we make the following adjustments, we can return our expected results

 public static string GetPinyin(string str)
{
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < str.Length; i++)
    {
        if (str[i] > 127)
        {
            string pinyin = Pinyin.GetPinyin(str[i]);
            sb.Append(pinyin);
            // 如果是最后一位，就不用追加空格
            if (i == str.Length - 1)
                continue;
            // 如果不是最后一位，但下一位是符号，也不用追加空格
            if (char.IsPunctuation(str[i+1]))
                continue;
            sb.Append(" ");
            continue;
        }
        sb.Append(str[i]);
    }
    return sb.ToString();
}

let's test

 string str = GetPinyin("Xiao Huang 本黄。");
Console.WriteLine(str);

The output is

Xiao Huang ben huang.

Just sauce!