Question

i have a form with 6 textboxes and a delete button.that i want to do is to read a text file and save it into a list.after that i want to give a value at the textbox1 and delete the row from the list that this value exists.with this code(i have already done) delete all the values from the text file.what should i change to the code?i use Microsoft Visual C# 2010 Express.

   List<string> StoreItems;

   public Form1()
   {
       InitializeComponent();

       filePath = @"C:\Users\v\Desktop\text.txt";

       StoreItems = new List<string>();
   }



  private void button3_Click(object sender, EventArgs e)
    {


        using (var streamReader = new StreamReader(filePath, Encoding.Default))
        {
            while (!streamReader.EndOfStream)
            {
                StoreItems.Add(streamReader.ReadLine());
            }
        }
        using (var streamWriter = new StreamWriter(filePath, false, Encoding.Default))
        {
            foreach (string line in StoreItems)
            {
                if(line == textBox1.Text)//remove all from the list
                StoreItems.Remove(line);
            }
        }

    }

Answer 1

You can use RemoveAll().

Removes all the elements that match the conditions defined by the specified predicate.

There’s no need for explicit iteration over the list. You can just call it like this:

StoreItems.RemoveAll(item => item == textBox1.Text);

You also forgot to write the list back to the file. I think you want code like this:

using (var streamReader = new StreamReader(filePath, Encoding.Default))
{
    while (!streamReader.EndOfStream)
    {
        StoreItems.Add(streamReader.ReadLine());
    }
}

StoreItems.RemoveAll(item => item == textBox1.Text);
using (var streamWriter = new StreamWriter(filePath, false, Encoding.Default))
{
    foreach (string line in StoreItems)
    {
        streamWrite.WriteLine(line);
    }
}