Refresh SQLDataReader on button click

Question

Same as the title and using C#. Anyone know how to do this? I have a bunch of data read into a list box but the data doesn't refresh unless I restart the windows form. anyone know how to refresh it on a button click event?

   {

                SqlConnection conn = new SqlConnection();
                conn.ConnectionString = (@"Data Source=.\SQLEXPRESS;AttachDbFilename=C:\Users\John\Desktop\DB\DB\DB\setup.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True");
                conn.Open();

                SqlCommand cmd = new SqlCommand
                ("SELECT PEOPLE " + "FROM Workers", conn);

                try
                {
                    SqlDataReader sdr = cmd.ExecuteReader();

                    while (sdr.Read())
                    {
                        listBox1.Items.Add(sdr["people"].ToString());
                    }

                    sdr.Close();
                }

                catch (SqlException ex)
                {
                    MessageBox.Show(ex.Message);
                }

                finally
                {
                    conn.Close();
                }

            }

This is in windows form Load. So i'm looking to add a button on my form which refreshes the listbox items list

where did you put your code? Please commit part of your code! — MUG4N
– MUG4N, Commented Apr 28, 2012 at 22:06
Put that code in a method(f.e. "getWorkers") and call it from form's load and button's click event-handlers. — Tim Schmelter
– Tim Schmelter, Commented Apr 28, 2012 at 22:15
Sorry i'm a bit of a newbie, i've created the class but how do I call it? — user1353517
– user1353517, Commented Apr 28, 2012 at 22:23

Kishore Kumar · Accepted Answer · 2012-04-28 22:55:25Z

2

Add a Method

private void ShowPeople()
{
    // Put your code;
}

and then use the same in your button click

private void Button_Click(object sender,EventArgs e)
{
    ShowPeople();
}

edited Apr 28, 2012 at 22:55

answered Apr 28, 2012 at 22:32

Kishore Kumar

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1 Comment

Tim Schmelter Over a year ago

You should at least have named the method better(f.e. private IList<String> getWorkers() or private void addWorkers())

MUG4N · Accepted Answer · 2012-04-28 22:30:30Z

0

To reload data over your sqldatareader (at least I guess you mean set by using the word "refresh") by pressing a button you simply have to access the database again with the same code you are already using. But the important point here is, that you are using a bad design. Therefore I point out an article (30 mins to read) which helped me a lot to improve my code and therefore got rid of code duplication.

Please read: http://imar.spaanjaars.com/416/building-layered-web-applications-with-microsoft-aspnet-20-part-1

After you have read this article I will promise you that you will have a better understanding of how you have to access data in the database within your application

edited Apr 28, 2012 at 22:30

answered Apr 28, 2012 at 22:20

MUG4N

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2 Comments

Tim Schmelter Over a year ago

Why is "SELECT PEOPLE " + "FROM Workers" open for SQL-Injection? There's not even one parameter in this sql query. It's the same as SELECT PEOPLE FROM Workers (what OP should use to avoid misunderstandings).

user1353517 Over a year ago

Thanks for the tips ^^. @TimSchmelter how do I call the method i've just created from form load and the button click?

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