How to Convert between Romaji and Hiragana/Katakana

• Download RomajiToKana.rar - 43.7 KB
• Download RomajiToKana.zip - 46.6 KB

Introduction

Few years ago, when I developed a Japanese translation tool, I realized that user may not have a Japanese IME on their PC, so they cannot input a Japanese Text in my tool's textbox. Then, I wrote a method to convert between Romaji and Kana. The trick is about how I made my database (the order is the most important).

Using the Code

First, declare a List to store database:

private List<string> Database = new List<string>();

Convert Mode enum:

enum Mode
{
    Hiragana,
    Katakana,
    Romaji
}

Read data from text file:

private void GetDatabase()
{
    using (System.IO.StreamReader sr = new System.IO.StreamReader("Database.txt"))
    {
        while (!sr.EndOfStream)
        {
            string splitMe = sr.ReadLine();
            Database.Add(splitMe);
        }
    }
}

Convert method:

private string Convert(string text, Mode convertMode)
{
    text = text.ToLower();
    
    string roma = string.Empty;
    string hira = string.Empty;
    string kata = string.Empty;
    
    foreach (string row in Database)
    {
        var split = row.Split('@');
        roma = split[0];
        hira = split[1];
        kata = split[2];
        
        switch (convertMode)
        {
            case Mode.Romaji:
                text = text.Replace(hira, roma);
                text = text.Replace(kata, roma.ToUpper());
                break;
            case Mode.Hiragana:
                text = text.Replace(roma, hira);
                break;
            case Mode.Katakana:
                text = text.Replace(roma, kata);
                break;
        }
    }
    
    return text;
}

Points of Interest

This is a very simple code. Please download the source code and use this method when you have to deal with Japanese input. :)

EDIT: Thanks to Seishin#, I updated my code.