Question

I’m currently working on a program that converts japanese characters to english characters and the other way around.
It’s not working much though, For the last few days I’ve been trying everything to try and get it to work, it’s probably some small dumb problem but I just can’t find it. I’m pretty new to all this so any help is appreciated.

Now the problem is that it only wants to convert Romaji characters, however if change some code, more specifically if I change the following from “if” to else if, then it converts hiragana and katakana but NOT romaji..

        string fromtype = "";

        // Determines what type the character is currently
        // && fromtype == "" added to avoid weird unexplainable errors...
        if (CharacterTable.Select("Romaji = '" + character + "'") != null && fromtype == "")
        {
            fromtype = "Romaji";
        }
        else if (CharacterTable.Select("Hiragana = '" + character + "'") != null && fromtype == "")
        {
            fromtype = "Hiragana";
        }
        else if (CharacterTable.Select("Katakana = '" + character + "'") != null && fromtype == "")
        {
            fromtype = "Katakana";
        }

I’ve even tried removing this function that tries to automatically find what type the character is and do it with radiobuttons so that the user has to select it, but somehow it seems to do pretty much the same thing… So I’m totally confused at this point, any help is very much welcome.

Here is the full code:

public string CheckCharacter(string character, int RequestedCharType)
        {
            // RequestedCharType
            // 1 = Romaji
            // 2 = Hiragana
            // 3 = Katakana

            //-- Instantiate the data set and table
            DataSet CharacterDatabase = new DataSet();
            DataTable CharacterTable = CharacterDatabase.Tables.Add();

            //-- Add columns to the data table
            CharacterTable.Columns.Add("Romaji", typeof(string));
            CharacterTable.Columns.Add("Hiragana", typeof(string));
            CharacterTable.Columns.Add("Katakana", typeof(string));


            //-- Add rows to the data table
            CharacterTable.Rows.Add("a", "あ", "ア");
            CharacterTable.Rows.Add("i", "い", "イ");


            // Sets fromtype to the type the character(s) currently is/are
            string fromtype = "";

            // Determines what type the character is currently
            // && fromtype == "" added to avoid weird unexplainable errors...
            if (CharacterTable.Select("Romaji = '" + character + "'") != null && fromtype == "")
            {
                fromtype = "Romaji";
            }
            else if (CharacterTable.Select("Hiragana = '" + character + "'") != null && fromtype == "")
            {
                fromtype = "Hiragana";
            }
            else if (CharacterTable.Select("Katakana = '" + character + "'") != null && fromtype == "")
            {
                fromtype = "Katakana";
            }



           // generates a new variable to store the return in
           DataRow[] filteredRows = CharacterTable.Select(fromtype + " = '" + character + "'");

            // Return the converted character in the requested type
            foreach (DataRow row in filteredRows)
            {
                if (RequestedCharType == 1)
                {
                    return row["Romaji"].ToString();
                }
                if (RequestedCharType == 2)
                {
                    return row["Hiragana"].ToString();
                }
                if (RequestedCharType == 3)
                {
                    return row["Katakana"].ToString();
                }
            }


            // if it couldn't find the character, return the original character
            return character;
        }

Answer 1

Your problem is in your misunderstanding of how Select works. Select does not return null when there are no matches so your first if is always true. Instead you need to check whether there were any results which you can do with Enumerable.Any() (add using System.Linq):

if (CharacterTable.Select("Romaji = '" + character + "'").Any())
{
    fromtype = "Romaji";
}
else ...

Alternatively you can check the array length:

if (CharacterTable.Select("Romaji = '" + character + "'").Length > 0)
{
    fromtype = "Romaji";
}
else ...

• I’m not sure what the fromType == "" bit is all about this is surely not needed.
• Considering creating an enum type for your char types.
• This method can be made static.
• Consider using a switch statement instead of if (RequestedCharType == 1)
&c.