saving to and loading from, text file and dataGridView C#

Question

I am needing to have the ability to save data from a dataGridView to a .txt and then be able to load the same data back in to the appropriate spots. It is databound.

Here is the code that I have so far. I can save to file but, it will only load the first record in the file into the dataGridView. Any help is greatly appreciated!

private void LoadButton_Click(object sender, EventArgs e)
    {
        if (openFileDialog1.ShowDialog().Equals(DialogResult.OK))
        {
            cardlist = new List<Card>();
            using (System.IO.StreamReader file = new System.IO.StreamReader(openFileDialog1.FileName))
            {
                Card newcard = new Card();
                newcard.CardName = file.ReadLine();
                newcard.NumBorrowed = Convert.ToInt32(file.ReadLine());
                cardlist.Add(newcard);
            }
            dataGridView1.DataSource = cardlist;

        }
    }

    private void SaveButton_Click(object sender, EventArgs e)
    {
        if (saveFileDialog1.ShowDialog().Equals(DialogResult.OK))
        {
            using (System.IO.StreamWriter file = new System.IO.StreamWriter(saveFileDialog1.FileName))
                foreach (Card currentCard in cardlist)
                {
                    file.WriteLine(currentCard.CardName);
                    file.WriteLine(currentCard.NumBorrowed);
                }
        }
    }
    public class Card
    {
        public String CardName { get; set; }
        public int NumBorrowed { get; set; }
    }

You're only reading in two lines of your file in your LoadButton_Click function. Try looping until you get to the end of the file, similar to what you do in your SaveButton_Click function. — B L, Mar 14 '14 at 15:42
Was gonna say the same thing, I was looking at this thinking "I'm pretty sure there's meant to be another foreach loop there....hmmmm" — JBurnham, Mar 14 '14 at 15:43
Thank you both so much, I have spent the past 2 weeks working on this personal windows app and my brain is fried. I should have noticed that small detail. Thanks for the help! — BPratt93, Mar 14 '14 at 15:47

Sudhakar Tillapudi · Answer 1 · 2014-03-14T15:55:05.203

You need to iterate over all items in the file

Replace This:

using (System.IO.StreamReader file = new System.IO.StreamReader(openFileDialog1.FileName))
{
    Card newcard = new Card();
    newcard.CardName = file.ReadLine();
    newcard.NumBorrowed = Convert.ToInt32(file.ReadLine());
    cardlist.Add(newcard);
}

With This:

int lineCount=0;
string line=string.Empty;
using (System.IO.StreamReader file = new System.IO.StreamReader(openFileDialog1.FileName))
{
    Card newcard = new Card();
    while((line=file.ReadLine()) != null)
    {
    if(lineCount == 0)
    {
     newcard.CardName = line;
     lineCount = 1;
    }
    else if(lineCount == 1)
    {
     newcard.NumBorrowed = Convert.ToInt32(line);
     lineCount = 0;
    }
     cardlist.Add(newcard);
}

OR

int i=0;
foreach(var line in File.ReadLines(openFileDialog1.FileName))               
{                
    Card newcard = new Card();
    if(i==0)
    {
         newcard.CardName = line;
         i = 1;
    }
    else if(i==1)
    {
         newcard.NumBorrowed = Convert.ToInt32(line);              
         i=0;
    }
    cardlist.Add(newcard);
}

Nunners · Answer 2 · 2014-03-14T15:56:35.037

Try the following code :

using (System.IO.StreamReader file = new System.IO.StreamReader(openFileDialog1.FileName))
{
    string line;

    while ((line = file.ReadLine()) != null)
    {
        Card newcard = new Card();
        newcard.CardName = line;
        newcard.NumBorrowed = Convert.ToInt32(line);
        cardlist.Add(newcard);
    }
}

This will cause the code to loop through the file until it reaches a null line (i.e. End of file).

This will place the entire line inside both CardName and NumBorrowed.

For this to work correctly you will either need to read 2 lines per loop, like so :

string line;
string line2;

while ((line = file.ReadLine()) != null && (line2 = file.ReadLine()) != null) {
}

And then you can correct your code :

Card newcard = new Card();
newcard.CardName = line;
newcard.NumBorrowed = Convert.ToInt32(line2);
cardlist.Add(newcard);

Alternatively, you could change your file Format and instead of having 2 lines per info, you could condense it onto one line with a seperating value (i.e. Jake^50 where ^ is the seperator)

You then need to just modify the code to split the line into an array and pull the values from that.

dear your approach is right but please make sure that same line is not added to both `CardName` and `NumBorrowed`. — Sudhakar Tillapudi, Mar 14 '14 at 15:50
@SudhakarTillapudi You're right, I didn't think about his File's Layout. I'll add to the Answer about it. — Nunners, Mar 14 '14 at 15:52

safetyOtter · Answer 3 · 2014-03-14T16:47:16.623

If i had my druthers, I'd write my text file delimited with one record per line and then not worry that 1 bad line will mess up all the following lines, but with your current structure this should work and it has a little error checking.

        using (StreamReader reader = new StreamReader(openFileDialog1.FileName))
        {
            bool stillReading = true;
            while (stillReading)
            {
                string card, numBorrowed;
                card = reader.ReadLine();
                numBorrowed = reader.ReadLine();
                if (card != null && numBorrowed != null)
                {
                    int numB;
                    Card newcard = new Card
                    {
                        CardName = card,
                        NumBorrowed = Int32.TryParse(numBorrowed, out numB) ? numB : 0
                    };
                    cardlist.Add(newcard);
                }
                else
                {
                    stillReading = false;
                }
            } 
        }

saving to and loading from, text file and dataGridView C#

3 Answers3