ASP.Net MVC : Get query values with no key - asp.net-mvc

Question

I have URL: http://site.com/page.aspx?update
how do I check if that update value is present?
HttpValueCollection treats that as an entity with null key. I have tried:
var noKeyValues = Request.QueryString.GetValues(null);
if (noKeyValues != null && noKeyValues.Any(v=>v==update)) ...
but it gives me a frowny line, because GetValues' argument is decorated with [NotNull].
so I end up doing:
var queryValuesWithNoKey =
Request.QueryString.AllKeys.Select((key, index) => new { key, value = Request.QueryString.GetValues(index) }).Where(
item => item.key == null).Select(item => item.value).SingleOrDefault();
if (queryValuesWithNoKey != null && queryValuesWithNoKey.Any(v => v.ToLower() == "update")) live = true;
not the most elegant workaround. Is there a better way to get key-less value from query string?

Answer 1

You can use
Request.QueryString[null]
to retrieve a comma separated list of keys with no values. For instance, if your url is:
http://mysite/?first&second
then the above will return
first,second
In your case, you could just do something like:
if(Request.QueryString[null] == "update")
{
// it's an update
}

Answer 2

if that's the only key you would use
Request.QueryString.ToString() to get the "update" value

Answer 3

I know I'm late to the party, but this a function that I use for this kind of task.
internal static bool HasQueryStringKey(HttpRequestBase request, string key)
{
// If there isn't a value, ASP will not recognize variable / key names.
string[] qsParts = request.QueryString.ToString().Split('&');
int qsLen = qsParts.Length;
for (int i = 0; i < qsLen; i++)
{
string[] bits = qsParts[i].Split('=');
if (bits[0].Equals(key, StringComparison.OrdinalIgnoreCase))
{
return true;
}
}
return false;
}
You may need to update it so that it is case sensitive, or uses different arguments depending on your purposes, but this has always worked well for me.