Check if there are duplicates in TXT files using C#

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Hey everybody,

I'm trying to make a C# code that finds out if the input from the textbox field is already in a TXT file.
Currently I have the code below to store the Input from the textbox.

What I want is a check that go's through the TextSA.txt file and only checks for the ChildOrderInput.Text and if it already exists in that TXT file. The Date and OrderInputText should be ignored in this check.

C#

File.AppendAllText("textSA.txt", DateTime.Now.ToString("dd-MM-yyyy") + OrderInputText + " " + ChildOrderInput.Text + "\n" + Environment.NewLine); }

Do you guys have any ideas on how to do this?

Also if the check finds a duplicate it should give an error to the user that the ChildorderInput.Text is already in the file and then send the DateTime.Now back to the user.

Hope anyone can help me!

Thanks!

grtz Robert

What I have tried:

File.AppendAllText("textSA.txt", DateTime.Now.ToString("dd-MM-yyyy") + OrderInputText + " " + ChildOrderInput.Text + "\n" + Environment.NewLine); }

Posted 17-Aug-17 8:20am

Member 13366011

Updated 17-Aug-17 9:06am

Thomas Daniels

v2

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Comments

PIEBALDconsult 17-Aug-17 21:13pm

It's almost CSV, so why not use CSV and then access it as if it were a database?

BillWoodruff 18-Aug-17 3:09am

While you have two solid answers to your question ... taken literally ... now, I wonder why you are using reading/writing a file for this ... an "expensive" process.

If you want to see an example that uses efficient in-memory storage, just ask.

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OriginalGriff · Accepted Answer · 2017-08-17T08:36:00

Solution 1

Try:

C#

string strTheFile = File.ReadAllText(@"D:\Test Data\textSA.txt");
if (strTheFile.Contains(ChildOrderInput.Text))
    {
    Console.WriteLine("Found!");
    }

Posted 17-Aug-17 8:36am

OriginalGriff

Thomas Daniels · Accepted Answer · 2017-08-17T08:38:00

You can do this:

Read the file line-by-line.
For each file:
1. Split into two parts by " " and take the second part. That gives you the previously saved ChildOrderInput. Note: this will not work of OrderInputText can possibly contain spaces; because, if that is possible, a space is not a clear separator for OrderInputText and ChildOrderInput.Text. So if OrderInputText can contain spaces, use another separator than " ".
2. If that saved ChildOrderInput equals the current one, break the loop and show the error.

(As a side note, I don't see the point of "\n" + Environment.NewLine - if you want two newlines, you better use Environment.NewLine + Environment.NewLine)

C#

bool displayError = false;
using (StreamReader sr = new StreamReader("textSA.txt"))
{
    while (sr.Peek() > -1)
    {
        string line = sr.ReadLine();
        if (!string.IsNullOrWhiteSpace(line))
        {
            string parts = line.Split(new char[] { ' ' }, 2);
            if (parts.Length < 2) { /* the line isn't in the correct format; handle it correctly if it can happen */ }

            string previousChildOrderInput = parts[1];
            if (previousChildOrderInput.Equals(ChildOrderInput.Text))
            {
                displayError = true;
                break;
            }
        }
    }
}
if (displayError)
{
    // display error

    // Displaying it here rather than inside the loop makes sure that the file is already closed before the error message is displayed.
}