ASP.NET QueryString without equals sign

Question

When I have a url like:

http://www.mysite.com/?MyTest=

MyTest shows up as a key in the querystring of the request object.

If I remove the = sign like:

http://www.mysite.com/?MyTest

It no longer shows up in the querystring keys (or AllKeys if you prefer).

How can I determine whether this key exists or not?

score 4 · Accepted Answer · edited May 23 '17 at 12:29

4

This is quite odd behaviour, without the = sign the QueryString object returned by the Request has a Count of 1 with a value of MyTest and a key of null.
You could test the QueryString to see if it contains the value you are expecting:

if(Request.QueryString.ToString().Contains("MyTest"))
{
    // Do stuff
}

Edit: this answer gives a bit more explanation as to what is going on with keyless parameters (scroll past the accepted answer).

edited May 23 '17 at 12:29

Community

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answered Mar 08 '12 at 16:59

Andy Rose

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Since the contains method is case-sensitive, you might want to convert the strings to upper for comparison. Request.QueryString.ToString().ToUpper().Contains("MYTEST") – DaveB Mar 08 '12 at 17:22
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The proper way based on the answer from the edit is `(Request.QueryString.GetValues(null) ?? new string [0]).Contains("MyTest")` – eitanpo Jun 14 '12 at 12:58

Max Toro · Answer 2 · 2012-03-08T18:24:23.807

1

I believe you can do Request.QueryString[null] or Request.QueryString.GetValues(null).

Without the equal sign MyTest is no longer a key, but a key-less value, you use null to get those. To check for both cases do this:

bool myTestPresent = Request.QueryString["MyTest"] != null
   || Request.QueryString.GetValues(null).Contains("MyTest", StringComparer.OrdinalIgnoreCase);

edited Mar 08 '12 at 18:24

answered Mar 08 '12 at 17:35

Max Toro

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Yuri Fedoseev · Answer 3 · 2012-03-08T17:43:50.403

0

You shoul use ToString() function

if (Request.QueryString.ToString() == "MyTest")
{
 //do something
}

edited Mar 08 '12 at 17:43

answered Mar 08 '12 at 17:22

Yuri Fedoseev

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ASP.NET QueryString without equals sign

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