C＃中的字典

Question

This program is meant to read in a csv file and create a dictionary from it, which is then used to translate a word typed into a textbox (txtINPUT) and output the result to another textbox (txtOutput).

The program doesnt translate anything and always outputs "No translation found." I've never used the dictionary class before so I dont know where the problem is coming from.

Thanks for any help you can give me.

    Dictionary<string, string> dictionary; 

    private void CreateDictionary()
    {
        //Load file
        List<string> list = new List<string>();
        using (StreamReader reader = new StreamReader("dictionarylist.csv"))
        {
            string line;
            while ((line = reader.ReadLine()) != null)
            {
                //Add to dictionary
                dictionary = new Dictionary<string, string>();
                string[] split = line.Split(',');
                dictionary.Add(split[0], split[1]);
            }
        }
    }
        private void btnTranslate_Click(object sender, EventArgs e)
    {
        CreateDictionary();

        string outputString = null;
        if (dictionary.TryGetValue(txtInput.Text, out outputString))
        {
            txtOutput.Text = outputString; 
        }
        else
        {
            txtOutput.Text = ("No translation found");
        }

    }

Answer 1

You are creating a new instance of a Dictionary each loop cycle, basically overwriting it each time you read a line. Move this line out of the loop:

// Instantiate a dictionary
var map = new Dictionary<string, string>();

Also why not load dictionary one time, you are loading it each button click, this is not efficient.

( >=.NET 3 ) The same using LINQ ToDictionary() :

usign System.Linq;
var map = File.ReadAllLines()
              .Select(l =>
               {
                    var pair = l.Split(',');
                    return new { First = pair[0], Second = pair[1] }
               })
              .ToDictionary(k => k.First, v => v.Second);

Answer 2

In your while loop, you create a new dictionary every single pass!

You want to create one dictionary, and add all the entries to that:

while ((line = reader.ReadLine()) != null)
{
    //Add to dictionary
    dictionary = new Dictionary<string, string>();  /* DON'T CREATE NEW DICTIONARIES */
    string[] split = line.Split(',');
    dictionary.Add(split[0], split[1]);
}

You should do it more like this:

List<string> list = new List<string>();
dictionary = new Dictionary<string, string>();  /* CREATE ONE DICTIONARY */
using (StreamReader reader = new StreamReader("dictionarylist.csv"))
{
    string line;
    while ((line = reader.ReadLine()) != null)
    {
        string[] split = line.Split(',');
        dictionary.Add(split[0], split[1]);
    }
}