Check out example codes for "C# sql connection con". It will help you in understanding the concepts better.

Code Example 1

private static void CreateCommand(string queryString,
    string connectionString)
{
    using (SqlConnection connection = new SqlConnection(
               connectionString))
    {
        SqlCommand command = new SqlCommand(queryString, connection);
        command.Connection.Open();
        command.ExecuteNonQuery();
    }
}

Code Example 2

using System;
using System.Windows.Forms;
using System.Data.SqlClient;
namespace WindowsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        private void button1_Click(object sender, EventArgs e)
        {
            string connetionString = null;
            SqlConnection cnn ;
			connetionString = "Data Source=ServerName;Initial Catalog=DatabaseName;User ID=UserName;Password=Password"
            cnn = new SqlConnection(connetionString);
            try
            {
                cnn.Open();
                MessageBox.Show ("Connection Open ! ");
                cnn.Close();
            }
            catch (Exception ex)
            {
                MessageBox.Show("Can not open connection ! ");
            }
        }
    }
}

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