Question

When I create the file and append to it the rest of the information I now want to have the ability to read the text file then display the Month of a birthday thats listed in the file.
I want to be able to pull in just the info by birthday. So if I choose month 11 I want to pull in all the data entries that have a birthmonth of 11 by pushing button4.

This is what I have so far;

 private void close_Click(object sender, EventArgs e)
    {
        Close();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        writetext();
        reset();

    }
    public void writetext()
    {

        using (TextWriter writer = File.AppendText("filename.txt"))

        {
         writer.WriteLine("First name, {0} Lastname, {1} Phone,{2} Day of birth,{3} Month of Birth{4}", textBox1.Text, textBox2.Text, maskedTextBox1.Text, textBox4.Text, textBox3.Text);
         MessageBox.Show(String.Format("First Name,{0} Lastname, {1} Phone,{2} Day of birth,{3} Month of Birth{4}", textBox1.Text, textBox2.Text, maskedTextBox1.Text, textBox4.Text, textBox3.Text)); 
        }
        }
    public void reset()
    {
        textBox1.Text = "";
        textBox2.Text = "";
        textBox3.Text = "";
        textBox4.Text = "";
        maskedTextBox1.Text = "";
    }

    private void button3_Click(object sender, EventArgs e)
    {
        Close(); 
     }

    private void button2_Click(object sender, EventArgs e)


    {
        readfile(); 


    }

    private void label7_Click(object sender, EventArgs e)
    {

    }

    private void button4_Click(object sender, EventArgs e)
    {

    }
    public void readfile()
    {
        string[] lines = File.ReadAllLines("filename.txt");
        label6.Text = String.Join(Environment.NewLine, lines);
    }
}






 }

Answer 1

Same as Geoffrey but with C# and linq syntax:

You can filter the content of your file using the birth date and store it in a new array this way:

string[] persons = File.ReadAllLines(Server.MapPath("filename.txt"));
IEnumerable<string> personsWithBirthday =
  from p in persons
    where p.Contains("1980-08-21")
      select p;
foreach (var person in personsWithBirthday)
 Response.Write(person);

I would recommend you to define a standard date format in order to easily grab all the persons matching the search criteria.