asp.net IF条件语句

Question

当出现ID=12345678时，跳转到404  如下代码应该怎么改。谢谢if (Request["id"] != null)
                {
                    id = Request["id"].ToString().Trim();                    string result = GetHtml("http://download.csdn.net/source/"+id+".html");                 ｝

Answer 1

if (Request["id"] != null&&Request["id"]=="12345678")
                {
                    Response.Redirect("notfound.aspx");
                 ｝
else if(Request["id"]!=null)
{
id = Request["id"].ToString().Trim();                    string result = GetHtml("http://download.csdn.net/source/"+id+".html");}

Answer 2

if (Request["id"] != null)
                {
                    id = Request["id"].ToString().Trim();                    string result = id=="12345678"?GetHtml("notfound.aspx"):GetHtml("http://download.csdn.net/source/"+id+".html");                 ｝

Answer 3

 string result =Request["id"] != null? GetHtml("http://download.csdn.net/source/"+Request["id"].ToString()+".html"):GetHtml("notfound.aspx");

Answer 4

if (Request["id"] != null && Request["id"].ToString() == "12345678")
{
    Response.StatusCode = (int)System.Net.HttpStatusCode.NotFound;
}