Question

Hello there im having problem whenever i press the refresh button it keeps adding :/ how do i prevent it? its been my day 2 figuring this out and i failed 🙁

protected void Button1_Click(object sender, EventArgs e)
        {
            //Instantiate the connection with the database 
            using (SqlConnection myConnection = new SqlConnection("user id=username;" +
                                                                  "password=password;" +
                                                                  "trusted_connection=yes;" +
                                                                  "database=DataBaseConnection;" +
                                                                  "connection timeout=30;"))
            {
                //Open the Connection object
                myConnection.Open();

                //Instantiate a SQL Command with an INSERT query
                SqlCommand myCommand = new SqlCommand("INSERT INTO BasicInfo (Firstname,Surname) Values(@a,@b);", myConnection);

                if (TextBox1.Text !=null && TextBox2.Text != null)
                {
                    //Texbox 
                    myCommand.Parameters.AddWithValue("@a", TextBox1.Text);
                    myCommand.Parameters.AddWithValue("@b", TextBox2.Text);

                    //Execute the query
                    myCommand.ExecuteNonQuery();
                }
                else
                {
                    //Code HEre?
                }

Answer 1

One way to handle this problem is to do a Response.Redirect at the end of the Button1_Click event back to original page. The Response.Redirect will make the browser do a GET request for the page, so if the user hits F5 they’ll just redo the GET (and not POST the form again).

This approach is sometimes called the Post/Redirect/Get pattern. This blog post has a pretty good writeup of the approach:
http://blog.andreloker.de/post/2008/06/Post-Redirect-Get.aspx