[C#]Doubt

[TheEvilAnt]

I got a problem with a piece of code I want to modify the app.config with a textbox so I use this but it doesnt work it update but doesnt change the values:

 

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using MySql.Data.MySqlClient;
using MySql.Data.Types;
using System.Configuration;

namespace MySql
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
Update_ConData();
}

private void button2_Click(object sender, EventArgs e)
{
Set_ConData();
Update_ConData();
}
public void Update_ConData()
{
//Read parameters App.config
string server = ConfigurationManager.AppSettings["server"];
string db = ConfigurationManager.AppSettings["db"];
string user = ConfigurationManager.AppSettings["user"];
string pass = ConfigurationManager.AppSettings["pass"];
//Put the variables in the textboxes
textBox1.Text = Convert.ToString(server);
textBox2.Text = Convert.ToString(user);
textBox3.Text = Convert.ToString(pass);
textBox4.Text = Convert.ToString(db);
}
public void Set_ConData()
{
Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
string mito = "[CeNsOrEd]";
config.AppSettings.Settings["server"].Value = Convert.ToString(textBox1);
config.AppSettings.Settings["user"].Value = Convert.ToString(textBox2);
config.AppSettings.Settings["pass"].Value = Convert.ToString(textBox3);
config.AppSettings.Settings["db"].Value = Convert.ToString(textBox4);
config.Save(ConfigurationSaveMode.Modified);
}
}
}