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POHow to show listbox item in textBox using data from local database in C#
 

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  1. POHow to show listbox item in textBox using data from local database in C#
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    <p>Hi im new to programming and currently working on a project that lets a user enter its registration data into a local database using textBoxes. The code works that its adding the items into the database and after i press a "Show_users" button it displays them in the listBox_users listbox.</p> <p>My problem is that when i choose a name from the listBox_users it should dislay the data about the selected user in the upper textBox'es i used to enter the data in the first place using the event i created for the listBox_users, but im getting an error that "can't read data from database that is already closed".</p> <pre><code>namespace Userform { public partial class Form1: Form { SqlCeDataReader rdr; public Form1() { InitializeComponent(); } // Some code between... private void button_ShowUsers_Click(object sender, EventArgs e) //code that shows users in listBox { var dt = new DataTable(); string connectionString2 = @"Data Source=MyDatabase;Password=xxxxxx;"; using (var cn = new SqlCeConnection(connectionString2)) using (var cmd = new SqlCeCommand("Select * From Users", cn)) { cn.Open(); using (var reader = cmd.ExecuteReader()) { dt.Load(reader); var results = (from row in dt.AsEnumerable() select new { //UserID = row.Field&lt;int&gt;("ID"), FirstName = row.Field&lt;string&gt;("Firsname"), LastName = row.Field&lt;string&gt;("Lastname"), FullName = row.Field&lt;string&gt;("Firstname") + " " + row.Field&lt;string&gt;("Lastname") }).ToList(); listBox_users.DataSource = results; listBox_users.DisplayMember = "FullName"; rdr = cmd.ExecuteReader(); } } } //I made an event for the listBox_users: private void listBox_users_SelectedIndexChanged(object sender, EventArgs e) //event code that should show listbox selected data in the textBoxes { if (listBox_inimesed.SelectedItem != null &amp;&amp; rdr != null) { try { if (rdr.Read()) { textBox1_firstname.Text = rdr.GetString(1); textBox2_lastname.Text = rdr.GetString(2); textBox3_email.Text = rdr.GetString(3); textBox4_address.Text = rdr.GetString(4); dateTimePicker1.Value = rdr.GetDateTime(5); richTextBox_info.Text = rdr.GetString(6); } else MessageBox.Show("Object not found"); } finally { rdr.Close(); } } } } </code></pre>
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