How to determine why a link to a web service cannot be added to my project in VS2008?

Question

I have a VS2005 project containing a couple of web service links. The project was recently upgraded to VS2008, but now there is a problem with web links ... probably because they may not have been updated properly.

When I select Update web link, I get the following error:

"The value cannot be null. Parameter name: discoveryError% mexError", which is very useful.

Then I deleted the web link to add it again ...

The Add Web Link dialog box appears and successfully downloads information about each of the methods associated with the web service.

However, I cannot add the link because the button for this is inactive, and there is a text box called "Web Services Found at this URL:" which contains the text "Operation is invalid due to the current state of the object."

Now, finally, this brings me to my main question ... How to add this web link? Or even better, how do you know what is invalid in relation to the "current state of the object"?

Has anyone had a similar experience in VS2008?

Answer 1

I finally understood.

I used WebService Studio to better understand what is happening. He returned with the error message "Request Error with HTTP Status 407: Proxy Authentication Required" .... which let me know that I had to install a new security certificate ... the old one was expired.

I think this question answers the question of how to find more about what is invalid with respect to the web service.

Answer 2

I had the same issue on VS2010. In my case, the problem was a proxy server. I got wsdl from an external url. My solution: install proxy server in VS2010. Modify the devenv.exe.config file and add <defaultProxy> to <system.net> :

 <system.net> <defaultProxy enabled="true" useDefaultCredentials="true"> <proxy bypassonlocal="True" proxyaddress="http://yourproxyserver:port"/> </defaultProxy> </system.net> 

If the proxy comes from a .pac file, you can omit the <proxy> :

  <system.net> <defaultProxy enabled="true" useDefaultCredentials="true"> </defaultProxy> </system.net> 

Old post about a related issue:
http://fhtino.blogspot.it/2006/11/visual-studio-2005-proxy-problem-in-add.html

Answer 3

I got the same error: with a link to update from Visual Studio 2008

 "Value cannot be null. Parameter name: discoveryError % mexError 

I already fixed the ACL check in the project folder. Definitely, I needed to add IUSR to folder security ... and what is it!

I worked for me and I hope to help anyone ...

Answer 4

I do not know what caused this error for me. I could not add a link to the web service for the service, but I could add a link to the service. Sorry, I need a web reference.

So, I did the WSDL download to my machine. When VS 2012 asks for a reference URL, I entered the path on my machine into the WSDL file. This created a web link for me.

Then I went into reference.map and changed the location of the WSDL from the local path to the URL. I have not tried it yet, but I think it should work ... At least I created the created web link.

Answer 5

Someone was messing with my IIS. Anonymous authentication was disabled for the service, after it was re-enabled, this error message disappeared.