The name 'ConnectionState' does not exist in the current context

using System;
using System.Data.SqlClient;
using System.Text;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }

        private void btnCreateDatabase_Click(object sender, EventArgs e)
        {
            String str;
            SqlConnection myConn = new SqlConnection("Server=localhost;Integrated security=SSPI;database=master");

            str = "CREATE DATABASE MyDatabase ON PRIMARY" +
                "(NAME = MyDatabase_Data," +
                "FILENAME = 'C:\\MyDatabase.Data.mdf'," +
                "SIZE = 2MB, MAXSIZE = 10MB, FILEGROWTH = 10%)" +
                "LOG ON (NAME = MyDatabase_Log," +
                "FILENAME = 'C:\\MyDatabaseLog.ldf'," +
                "SIZE = 1MB," +
                "MAXSIZE = 5MB," +
                "FILEGROWTH = 10%)";
            SqlCommand myCommand = new SqlCommand(str, myConn);
            try
            {
                myConn.Open();
                myCommand.ExecuteNonQuery();
                MessageBox.Show("DataBase is Created Successfully", "MyProgram", MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
            catch (System.Exception ex)
            {
                MessageBox.Show(ex.ToString(), "MyProgram", MessageBoxButtons.OK,MessageBoxIcon.Information);
            }
            finally
            {
                if (myConn.State == ConnectionState.Open)
                {
                    myConn.Close();
                }
            }
        }
    }
}

The name 'ConnectionState' does not exist in the current context compile error appears in this Microsoft source code. Why? How is it corrected?