topic Re: Export To Excel - Null Reference Error in ArcGIS API for Silverlight Questions

Export To Excel - Null Reference Error

GreggBreton — Fri, 03 Aug 2012 20:30:21 GMT

Hello,

I downloaded the following solution file
http://forums.arcgis.com/threads/45538-How-to-make-Export()-is-work-with-ArcGIS-API-for-Silverlight!

Export.zip
QueryWithoutMap.zip

Executed and queried the default "New" clicked the export button and works fine
Then tried "S", returned records and tried to export and received "Null Reference Exception"

Use the new keyword to create an object instance
Check to determine if the object is null before calling the method

private static string GetValue(FrameworkElement frameworkElement)
        {
            return frameworkElement is TextBlock ? (frameworkElement as TextBlock).Text : frameworkElement.ToString();
        }

If someone could illustrate how the above would be written to avoid the null exception error

Thank you

Re: Export To Excel - Null Reference Error

deleted-user-ATjHIWsdQYmT — Sat, 11 Dec 2021 18:41:05 GMT

Gregg-
Try:


private static string GetValue(FrameworkElement frameworkElement){ return frameworkElement is TextBlock & (frameworkElement != null) ? (frameworkElement as TextBlock).Text : frameworkElement.ToString();}

This should trap if your frameworkElement is NOT null

Re: Export To Excel - Null Reference Error

GreggBreton — Sat, 04 Aug 2012 00:06:17 GMT

Andrew -

I still receive the same Null Exception?

Re: Export To Excel - Null Reference Error

DominiqueBroux — Tue, 07 Aug 2012 07:54:38 GMT

Try:

private static string GetValue(FrameworkElement frameworkElement) {     return frameworkElement == null ? null          :( frameworkElement is TextBlock ? (frameworkElement as TextBlock).Text : frameworkElement.ToString()); }

Re: Export To Excel - Null Reference Error

JoeHershman — Sat, 11 Dec 2021 18:41:08 GMT

Nothing incorrect about the above code but I think this is a bit easier to read and I think should work.


        private static string GetValue(FrameworkElement frameworkElement)
        {
            var textBlock = frameworkElement as TextBlock;
            if ( textBlock == null ) return null;


            return textBlock.Text;
        }

Re: Export To Excel - Null Reference Error

GreggBreton — Tue, 07 Aug 2012 19:50:53 GMT

Yes, that did the trick

It allowed me to download the file, but when I open the csv file it displays the following:

File is in a different file format than specified by the extension

[ATTACH=CONFIG]16753[/ATTACH]

Excel has detected that the file is a SYLK file, but cannot load it, either the file has errors or is not in SYLK format

[ATTACH=CONFIG]16755[/ATTACH]

After the above messages, the file opens and looks fine.

Would the errors be caused by the REST service data not being in correct format? The script trying to conform to the csv format? or something else that you may have run into..

Thank you Dominique

Re: Export To Excel - Null Reference Error

GreggBreton — Tue, 07 Aug 2012 20:11:28 GMT

Yes, that did the trick

It allowed me to download the file, but when I open the csv file it displays the following:

File is in a different file format than specified by the extension

[ATTACH=CONFIG]16756[/ATTACH]

Excel has detected that the file is a SYLK file, but cannot load it, either the file has errors or is not in SYLK format

[ATTACH=CONFIG]16757[/ATTACH]

After the above messages, the file opens and looks fine.

Would the errors be caused by the REST service data not being in correct format? The script trying to conform to the csv format? or something else that you may have run into..

Thank you Dominique

Re: Export To Excel - Null Reference Error

deleted-user-ATjHIWsdQYmT — Tue, 07 Aug 2012 21:56:48 GMT

Yes, that did the trick

It allowed me to download the file, but when I open the csv file it displays the following:

File is in a different file format than specified by the extension

[ATTACH=CONFIG]16756[/ATTACH]

Excel has detected that the file is a SYLK file, but cannot load it, either the file has errors or is not in SYLK format

[ATTACH=CONFIG]16757[/ATTACH]

After the above messages, the file opens and looks fine.

Would the errors be caused by the REST service data not being in correct format? The script trying to conform to the csv format? or something else that you may have run into..

Thank you Dominique

Gregg,
Check out this link:
http://support.microsoft.com/kb/323626

If your first field name is "ID", try trapping it in your export code by changing it to "id" or adding an apostraphe like the article says. Another workaround would be to hide the "ID" field from your map service unless it's necessary.

Re: Export To Excel - Null Reference Error

GreggBreton — Tue, 07 Aug 2012 22:38:43 GMT

I will follow up on thread and give it a try

Thank you

Re: Export To Excel - Null Reference Error

deleted-user-ATjHIWsdQYmT — Wed, 08 Aug 2012 13:46:15 GMT

I will follow up on thread and give it a try

Thank you

Gregg, Quick solution - change the Header text of the first column from "ID" to something else. It'll solve the problem.

Re: Export To Excel - Null Reference Error

GreggBreton — Wed, 08 Aug 2012 19:27:21 GMT

Just changed ID to id and it worked fine

That will do it....Thank you