Can we detect when google bot crawl my page ASP.Net

Question

i need to programmatically detect when Google bot or any other search engine bot crawl our web site page. i have logic in Application_BeginRequest of my global.asax that when any page is requested then i try to read two cookies value and if anyone is missing then i redirect user to a specific page from where user select country and from there few cookies are dropped in user pc.

protected void Application_BeginRequest(Object sender, EventArgs e)
{
    string strCountryCookie = BBAreman.CountryCookie.GetCookieValue();
    string strShippingCookie = BBAreman.CountryCookie.GetShippingCookieValue();

    if (Request.Url.ToString().IndexOf(".asmx") == -1)
    {
    if (strCountryCookie.Trim() == "" || strShippingCookie.Trim() == "")
    {
        if (Request.Url.GetLeftPart(UriPartial.Authority).ToString() + "/index.aspx?ShowCountry=true" != HttpContext.Current.Request.Url.ToString())
        {
        Response.Redirect("~/index.aspx?ShowCountry=true");
        }
    }
    }
}

now when Google bot access any of our page then bot is redirecting to a specific page and not being able to access any of page. as a result our web site is loosing ranking.

i never face this situation.so guys please guide me how to handle this situation. thanks

EDIT

i got a routine like

If(Request.Browser.Crawler) Then
    'this is a web bot
Else
    'this is a regular user
End If

i guess the above way i can detect that bot is crawling my page or any human? just tell me am i on right track or not ?

Solved

i solved it this way

public class Utility
{
public static bool IsCrawlByBot()
    {
        List<string> Crawlers = new List<string>()
        {
            "googlebot","bingbot","yandexbot","ahrefsbot","msnbot","linkedinbot","exabot","compspybot",
            "yesupbot","paperlibot","tweetmemebot","semrushbot","gigabot","voilabot","adsbot-google",
            "botlink","alkalinebot","araybot","undrip bot","borg-bot","boxseabot","yodaobot","admedia bot",
            "ezooms.bot","confuzzledbot","coolbot","internet cruiser robot","yolinkbot","diibot","musobot",
            "dragonbot","elfinbot","wikiobot","twitterbot","contextad bot","hambot","iajabot","news bot",
            "irobot","socialradarbot","ko_yappo_robot","skimbot","psbot","rixbot","seznambot","careerbot",
            "simbot","solbot","mail.ru_bot","spiderbot","blekkobot","bitlybot","techbot","void-bot",
            "vwbot_k","diffbot","friendfeedbot","archive.org_bot","woriobot","crystalsemanticsbot","wepbot",
            "spbot","tweetedtimes bot","mj12bot","who.is bot","psbot","robot","jbot","bbot","bot"
        };

        string ua = HttpContext.Current.Request.UserAgent.ToLower();
        bool iscrawler = Crawlers.Exists(x => ua.Contains(x));
        return iscrawler;
    }
}

protected void Application_BeginRequest(Object sender, EventArgs e)
        {
            //if (!Request.Browser.Crawler)
            if (!Utility.IsCrawlByBot())
            {
                string strCountryCookie = BBAreman.CountryCookie.GetCookieValue();
                string strShippingCookie = BBAreman.CountryCookie.GetShippingCookieValue();
                if (Request.Url.ToString().IndexOf(".asmx") == -1)
                {
                    if (strCountryCookie.Trim() == "" || strShippingCookie.Trim() == "")
                    {
                        if (Request.Url.GetLeftPart(UriPartial.Authority).ToString() + "/index.aspx?ShowCountry=true" != HttpContext.Current.Request.Url.ToString())
                        {
                            Response.Redirect("~/index.aspx?ShowCountry=true");
                        }
                    }
                }
            }
        }