compiler error c# CS0103: The name 'CommandType' does not exist in the current conte

[pratheek]

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data.SqlClient;
using System.Web.Security;
using System.Data;
 
public partial class Login : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
 
    }
    protected void Button1_Click(object sender, EventArgs e)
    {
 
        SqlConnection Cn = new SqlConnection("server=nikhil;database=mydb;uid=sa;pwd=123");
        SqlCommand Cmd = new SqlCommand();
        Cmd.Connection = Cn;
        Cmd.CommandText = "validateuser";
        Cn.Open();
        Cmd.CommandType =CommandType.StoredProcedure;
        Cmd.Parameters.Clear();
        Cmd.Parameters.AddWithValue("", TextBox1.Text);
        Cmd.Parameters.AddWithValue("", TextBox2.Text);
        SqlDataReader Dr = Cmd.ExecuteReader();
        if (Dr.Read())
            FormsAuthentication.RedirectFromLoginPage(TextBox1.Text, false);
        else
            Label1.Text = "user id/password is wrong";
 
        Dr.Close();
        Cn.Close();
    }
}