错误6嵌入的语句不能是声明或标记语句string,怎么办？
 protected void Button1_Click(object sender, EventArgs e)
    {
        if (RadioButtonList1.SelectedValue != "")
        {
            if(Request.Cookies["ip"]!=null)
                string newip=Request.Cookies["ip"].Value;
            if(newip==Request.UserHostAddress)
                Response.Write("<script>alert('你已经投票！')</script>");
            return;
    

            int selectvalue = Convert.ToInt32(RadioButtonList1.SelectedValue);

            switch (selectvalue)
            {
                case 1:
                    read2write(1);
                    break;
                case 2:
                    read2write(2);
                    break;
                case 3:
                    read2write(3);
                    break;
                case 4:
                    read2write(4);
                    break;
            }
        }
}
------解决方案--------------------

string newip = string.Empty;

 if(Request.Cookies["ip"]!=null)

       newip=Request.Cookies["ip"].Value;