getting data between two dates

using (SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["con"].ConnectionString))

{

using (SqlCommand cmd = new SqlCommand("SELECT * FROM [piechart] where Date BETWEEN '" + txtDate.Text + "' AND '" +txtDate1.Text + "'"))

{

using (SqlDataAdapter sda = new SqlDataAdapter())

{

cmd.Connection = con;

sda.SelectCommand = cmd;

using (DataTable dt = new DataTable())

{

sda.Fill(dt);

// GridView1.DataSource = dt;

GridView1.DataBind();

}

}

}

}