Login Another Site And Open Page By C#.net

  protected void login1User(object sender, EventArgs e)
    {
    SqlConnection con = new SqlConnection("Data Source=SYSTEM1;Initial Catalog=master;Integrated Security=True");
    SqlCommand cmd = new SqlCommand();
    cmd.Connection = con;
    string sql;
    sql = "select *from user1 where uname ='" + TextBox1.Text + "' and pwd = '" + TextBox2.Text + "'";
    cmd.CommandText = sql;
    con.Open();
    SqlDataReader dr = cmd.ExecuteReader();
    if (dr.Read())
    {
        Response.Redirect("User.aspx");
    }
}