Gravar dados no banco SQLServer

[andyeverson]

Então galera to com dificuldade nesse código na parte final dele

gravar.ExecuteNonQuery();

toda vez que vou gravar os

os dados ele informa que nao esta conectado. como resolvo isso ai galera

desde ja agraço a ajuda...

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 System.Data.SqlClient;

namespace SQLServer
{
    public partial class Form1 : Form
    {
        SqlConnection conectar;
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {

            conectar = new SqlConnection(
                @"Data Source=localhost\MSSQLSERVER1;"
                + "Initial Catalog=aula;"
                + "Integrated Security=SSPI;");
           conectar.Open();
        }


        private void Form1_FormClosed(object sender, FormClosedEventArgs e)
        {

            if (conectar.State == ConnectionState.Open)
            {
                conectar.Close();
            }
        }



        private void button2_Click(object sender, EventArgs e)
        {
            txtEmail.Text = "";
            txtNascimento.Text = "";
            txtNome.Text = "";
            txtTelefone.Text = "";
        }

        private void button4_Click(object sender, EventArgs e)
        {
            txtEmailM.Text = "";
            txtNascimentoM.Text = "";
            txtNomeM.Text = "";
            txtTelefoneM.Text = "";
            txtCodigo.Text = "";
        }

        private void button5_Click(object sender, EventArgs e)
        {
            txtCodigoD.Text = "";
            txtEmailD.Text = "";
            txtNascimentoD.Text = "";
            txtNomeD.Text = "";
            txtTelefoneD.Text = "";

        }

        private void button1_Click(object sender, EventArgs e)
        {

            SqlDataReader sqldr = null;
            SqlConnection con = null;
            SqlCommand cmd = null;
            try
            {

                string ConnectionString = @"Data Source=localhost\MSSQLSERVER1;"+ "Initial Catalog=aula;"+ "Integrated Security=SSPI;";               
                con = new SqlConnection(ConnectionString);
                con.Open();

                string CommandText = "SELECT  * " +"FROM contatos " +"WHERE (nome LIKE @criterio)";



                cmd = new SqlCommand(CommandText);
                cmd.Connection = con;

                cmd.Parameters.Add(new SqlParameter("@criterio",System.Data.SqlDbType.VarChar,80,"nome"));



                cmd.Parameters["@criterio"].Value = txtcriterio.Text+"%";

                sqldr = cmd.ExecuteReader();
                lbDados.Items.Clear();
                if (sqldr.HasRows)
                {
                    while (sqldr.Read())
                    {
                        lbDados.Items.Add("    " + sqldr["id_contato"].ToString() + " - " + sqldr["nome"].ToString() + 
                        " - " + sqldr["telefone"].ToString() + " - " + sqldr["email"].ToString()+" - "+ sqldr["nascimento"].ToString());

                    }
                }
            }
            catch (Exception ex)
            {

                MessageBox.Show(ex.Message);
            }
            finally
            {

                if (sqldr != null)
                    sqldr.Close();
                if (con.State == ConnectionState.Open)
                    con.Close();
            }


        }

        private void btnGravar_Click_1(object sender, EventArgs e)
        {
            SqlCommand gravar = new SqlCommand("insert into contatos (nome, email, telefone, nascimento) values (@p_nome, @p_email, @p_telefone, @p_nascimento)");

            gravar.Parameters.Add(new SqlParameter("@p_nome", this.txtNome.Text));
            gravar.Parameters.Add(new SqlParameter("@p_email", this.txtEmail));
            gravar.Parameters.Add(new SqlParameter("@p_telefone",this.txtTelefone.Text));
            gravar.Parameters.Add(new SqlParameter("@p_nascimento", this.txtNascimento.Text));

           // conectar.Open();
            gravar.ExecuteNonQuery();
            conectar.Close();



        }
    }
}