How check if Request.QueryString is not empty

Question

I have my own HandleErrorAttribute, which reads data from Exception and HttpContext, insert them into template and send an e-mail to administrator. It usually works fine, but it some cases it breaks, when trying to check if QueryString is not empty.

var requestParams = "";
if (context.Request.QueryString != null && context.Request.QueryString.Keys.Count > 0)
{
    foreach (String key in context.Request.QueryString.Keys)
    {
        requestParams += key + ": " + context.Request.QueryString[key] + "<br />";
    }
}
else
{
    requestParams = "[ no query string data ]";
}

It breaks when checking condition (NullReferenceException), even if I can see in debug, that QueryString is not null and the Keys.Count is equal to 0.

What am I missing here? How to do a proper check for an empty QueryString?

Stacktrace:

w System.Web.Hosting.IIS7WorkerRequest.GetQueryStringPtr(Int32& length)
w System.Web.Hosting.IIS7WorkerRequest.GetQueryStringRawBytes()
w System.Web.HttpRequest.get_QueryStringBytes()
w System.Web.HttpRequest.FillInQueryStringCollection()
w System.Web.HttpRequest.EnsureQueryString()
w System.Web.HttpRequest.get_QueryString()
w System.Web.HttpRequestWrapper.get_QueryString()
w project.Infrastructure.Attributes.ErrorHandlingAttribute.BuildErrorEmail(Exception exc, HttpContextBase context) w c:\Users\Marcin Bigoraj\Documents\Visual Studio 2012\Projects\project\Infrastructure\Attributes\ErrorHandlingAttribute.cs:wiersz 141
w project.Infrastructure.Attributes.ErrorHandlingAttribute.<>c__DisplayClass2.<OnException>b__1() w c:\Users\Marcin Bigoraj\Documents\Visual Studio 2012\Projects\project\Infrastructure\Attributes\ErrorHandlingAttribute.cs:wiersz 182
w System.Threading.Tasks.Task.InnerInvoke()
w System.Threading.Tasks.Task.Execute()

I just tested this in a controller, and it works like a charm, without any exceptions. Could you post more related code? Maybe the whole attribute if possible? — schei1
– schei1, Commented Jul 11, 2014 at 12:02

Chris Barlow · Accepted Answer · 2014-07-11 12:25:02Z

7

Check this code

if (Request.QueryString.Keys.Count > 0)
{

}

edited Jul 11, 2014 at 12:25

Chris Barlow

3,3124 gold badges34 silver badges52 bronze badges

answered Jul 11, 2014 at 12:03

ARUNRAJ

4896 silver badges16 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

SearchForKnowledge Over a year ago

This is GREAT! checking to see if it's null wasn't working for me. +1

शेखर · Accepted Answer · 2014-07-11 11:24:27Z

0

You can determine if there are any values in the QueryString by checking its count:

Request.QueryString.Count > 0;

It is sufficient.

answered Jul 11, 2014 at 11:24

शेखर

17.6k14 gold badges64 silver badges123 bronze badges

3 Comments

user1859022 Over a year ago

-1 if the QueryString is null you will get an exception

Marcin Bigoraj Over a year ago

Even with this I have the same exception.

user1859022 Over a year ago

@Șhȇkhaṝ sry I would but I cant: "your last answer was ... ago. Your vote is locked..."

Collectives™ on Stack Overflow

How check if Request.QueryString is not empty

2 Answers 2

1 Comment

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related