Problem using webclient : (illegal characters in Path) error

Question

I am facing problem while making web request by WebClient.
I am making request to google map geocode apge to findout the longitude and latitude of particular address.
Here is my code to do that :

Dim QueryString As String
Dim responseText As String = ""
Dim WC As New Net.WebClient
Dim SR As IO.StreamReader
 
QueryString = "?q=" & getValidAddressString() & "&output=csv&key=" & ConfigurationManager.AppSettings("GeoCodeKey")
 
Dim redirectURL As String = ConfigurationManager.AppSettings("GeoCodeURL") & QueryString
SR = New IO.StreamReader(WC.OpenRead(redirectURL))
responseText = SR.ReadToEnd()
SR.Close()
 
processResponseText(responseText)

The strange thing is that for same address string, the code is working without any problem in one page. While the same code(have copy pasted) in another page is throwing the following error :

Illegal characters in path.

Exception Details: System.ArgumentException

at System.Security.Permissions.FileIOPermission.HasIllegalCharacters(String[] str)
at System.Security.Permissions.FileIOPermission.AddPathList(FileIOPermissionAccess access, AccessControlActions control, String[] pathListOrig, Boolean checkForDuplicates, Boolean needFullPath, Boolean copyPathList)
at System.Security.Permissions.FileIOPermission..ctor(FileIOPermissionAccess access, String[] pathList, Boolean checkForDuplicates, Boolean needFullPath)
at System.IO.Path.GetFullPath(String path)
at System.Net.WebClient.GetUri(String path)
at System.Net.WebClient.DownloadData(String address)
at KG.GeoCodeHelper.Page_Load(Object sender, EventArgs e) in

Kiran Beladiya · Answer

For your information I am sending one of URL which is used in my webclient request. It is : http://maps.google.com/maps/geo?q=4610 N Fairfax DriveArlingtonVA22203United States of America&output=csv&key=ABQIAAAARTl5NX7JU30LDNhqaIGTBBT2yXp_ZAY8_ufC3CFXhHIE1NvwkxTi80XdAA-lXaRCoNVg8QSDNkrBMA Please note the key is what i am using for my localhost probably you will need your own google map api key. So the code becomes now : Dim redirectURL As String =  http://maps.google.com/maps/geo?q=4610 N Fairfax DriveArlingtonVA22203United States of America&output=csv&key=ABQIAAAARTl5NX7JU30LDNhqaIGTBBT2yXp_ZAY8_ufC3CFXhHIE1NvwkxTi80XdAA-lXaRCoNVg8QSDNkrBMA  dim SR As New IO.StreamReader(WC.OpenRead(redirectURL)) responseText = SR.ReadToEnd() SR.Close() FYI : I have stepped throught the debugger without that how could i post the stack trace in my previous post and one more thing the same code with same requet URL working in other page. Also please look at the stacktrace in my first post it is showing some FileIOPermission problem. I am wondering what is related to FIleIOPermission with webclient request or webrequest. MORE INFO: ----- The pages actually resides in two seprate virtual directories(In separate webprojects). The location of both pages are as follow the code specified above is running on both's Page_Load event: 1. Main virtual directory http://localhost/kg/GeoCodeHelper.aspx 2. Sub directory of main directory but itself is virtual directory residing complete new website. This CMS directory is virtual directory having full new website but is inside the main KG directory. http://localhost/kg/CMS/GeoCodeHelper.aspx I just want to know from experts that though I am making the webrequest the stacktrace shows the error has been throwed from fileIOPermission in hierarchy. So can anybody tell me what is related between File IO and web request?

Scott Lysle · Answer

Have you tried stepping through it to see what the string contains at the time of the submission (comparing it to the part where it is working correctly). What exactly is in the string?