в файле конфигурации :
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<appSettings>
<add key="ConnStr"
value="Data Source=(local);Integrated Security=SSPI;Initial Catalog=Proba;Persist Security Info=True;User ID=sa;/>
</appSettings>
</configuration>

в коде:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;
using System.Configuration;

namespace GalaryP
{
public partial class Form1 : Form
{
private System.Windows.Forms.DataGrid dataGrid1;


public Form1()
{
InitializeComponent();
SqlConnection con = new SqlConnection();
con.ConnectionString = ConfigurationSettings.AppSettings["ConnStr"].ToString;
con.Open();
SqlCommand Cmd = new SqlCommand();
Cmd.Connection = con;
Cmd.CommandText = CommandText;
SqlDataAdapter da = new SqlDataAdapter();
da.SelectCommand = Cmd;
DataSet ds = new DataSet();
da.Fill(ds, "ttable");
dataGrid1.DataSource = ds.Tables["ttable"].DefaultView;
con.Close();
}


}
}
выдает следующую ошибку:
Warning 1 'System.Configuration.ConfigurationSettings.AppSettings' is obsolete: 'This method is obsolete, it has been replaced by System.Configuration!System.Configuration.ConfigurationManager.AppSettings'
Помогите разобраться в чем проблема?