Error Message when running a workflow - Object reference not set to an instance of an object
Hello
I could really use some help. I am having an issue with a workflow. It is basically the Search by Schools workflow, but instead of using Zip Codes, I am using Electoral Wards. I have the work flow developed and it looks like it should work. Infact I can get as far as selecting a Ward and retrieving the schools within the ward, but when I click on a school or click on the search button I get this odd error Message. I have attached an image of the error message."Object reference not set to an instance of an object". I am not sure what to do now. Everything Points to the workflow executing properly until I go to select the schools that appear in the drop down list...or click on search. One other thing...I am really new to Workflow. I created this one just following the tutorial from Geocortex.
/customer/servlet/servlet.FileDownload?file=00P6000000elzrlEAA
Any help would be appreciated.
LJ
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The error is in an Assign activity in your workflow. Search your workflow for Assign activities.
I guess in the Value part (right side) of this Assign activity there is a variable referencing a Nothing value in stead of an object.
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Thank you Nico!
Yes, that is very helpful. I have at least now narrowed it down to where the error is, But no matter what I try I can`t figure it out. It still brings up the same error. I don`t know if it how I have written the code, or if it is how I defined the variable.
Still looking...
thanks for pointing me in the right direction.
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So what is the value on the right hand side of the Assign activity?
Ralph
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Hi Ralph,
ok, so when I run it in the simulator, the error shows up in the Assign activity and it looks like this:
I have three snap shots of what I am looking at, the activity builder - left adn right side and then my variables. The images are small so here is the code for the left side: "WARD='" +Ward.ToString() +"'"
And this is for the right side: "OBJECTID="+School.ToString()
My variables are as such:
btnResult - string
Ward - Object
School - Object
school_query - String
school_FS - FeatureSet
Hope this helps! thanks for your time!
/customer/servlet/servlet.FileDownload?file=00P6000000elzcuEAA
/customer/servlet/servlet.FileDownload?file=00P6000000elzjiEAA
/customer/servlet/servlet.FileDownload?file=00P6000000em1NPEAY
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Hi LJohnstone
Are you sure that Ward is actually being set to something. Odds are that Ward is actually null and therefore will give issues with the .ToString
You could probably drop the () off the .ToString also.
How are you setting Ward? (Setting as compared to declaring)
John, I agree with the use of the Alerts. Problems arise at times when using that strategy due to Alert being a Client-side activity and there may be variables in scope at the time that the Alert that is used that is not readily serialized on the Server-side such as DataTables. When going from Client-side to Server-side and vice versa all variables must be packaged up for transmission to the 'other side'
Regards
Ralph
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Thank you for getting back to me.
I know I am going to sound like a fool, but I am not sure what you mean exactly? I am on my own trying to figure this out and I am not a programmer. LOL!
Take a look at the snap shot below. The Ward will appear in the list, I can select it. It will filter the Schools for that ward and display them in the list. It will let me select a School. I get the error when I click on "Search". I removed the () and it made no difference. I am not sure what else it could be. Could it have something to do with the fact that the Data in the field that I am pulling from has both Text and numbers ie: WARD 10? or could it have something to do with the actual field in the shapefile in the GDB? I took a look at the data. The field is set for string and it is has the correct field name.
Thanks
Larisa
/customer/servlet/servlet.FileDownload?file=00P6000000elzYAEAY
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Hi Larisa
No intent to have people sounding like fools at all. In the design of your form, as shown in your screen shot, do you have something like the following set up?
/customer/servlet/servlet.FileDownload?file=00P6000000em185EAA /customer/servlet/servlet.FileDownload?file=00P6000000elzXzEAI
Except in your case I should have had the arrows pointing at the Combobox.
To make some more progress can you please open your workflow ie the .xaml file, in a text editor and paste the raw text into your next message then we can see a little more clearly what you are doing.
Regards
Ralph
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Hi Larisa
Yes you definitely need to set the output arguments as below.
/customer/servlet/servlet.FileDownload?file=00P6000000eltlJEAQ
See how it goes once you have made that change.
Regards
Ralph
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Larisa,
In the display form "Form to collect user input" you should set the Output arguments: for WARD this is the variable Ward and for SCHOOLS the variable School.
In the query task Query for Schools you should change thet query service url to " http://www.mappmycity.ca/arcgis/rest/services/MappMyCity/CityofWindsorOperationalMap/MapServer/57", I think.
Check the map service and layer ids in the Display Schools Featureset. If you want to show your selection in the map, I think Collection Name should be empty here.
Success.
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Hi Ralph,
I realised that I missed a step filling in my output arguments, so I thought...wow, problem solved... but no I added the variable names to the output arguments and I got an error message. I think it is how I build my ComboBox. But I can't see it. This is what I see.
/customer/servlet/servlet.FileDownload?file=00P6000000eltuzEAA
/customer/servlet/servlet.FileDownload?file=00P6000000elu20EAA
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Gentlemen,
I just wanted to say thank you for all your help, it has been invaluable. I think I have it working! I can select a ward, get a drop down list of the schools and THEN I can select a school (or all the schools) they show up in a list on the left hand side panel and a popup appears with all the additional information I want shown about the school. The problem is now....the zoom so selected is greyed out, so the user has no way of seeing where the school is on the map? Any ideas how I can get the zoom to working on that pop up? I am working in Silverlight and HTML5. I have this site developed for both. Here is the link to the Silverlight;
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It looks like you did not set 'Return Geometry' = True on the Query Task.
The School features found do not have Geometry, which I can tell 'Zoom Feature' command is disabled.
Check it out.
Munhwan
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Hi Munwhan,
hmmmm I must be missing something? This is what I ahve. I set the return geomerty to True, but nothing changed.
this is what I am looking at. Thanks!
/customer/servlet/servlet.FileDownload?file=00P6000000em1KMEAY
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ok. now I recommends to use Fiddler (refer https://support.geocortex.com/debug-essentials-using-fiddler-) to check out what the Request and Respond from QueryTask, and all workflow steps.
If possible, copy and paste your workflow file on this forum so that someone will check it for you.
Munhwan
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I guess it's because the SHAPE (or GEOMETRY) field is not included in the layer.
You should enable this in your MXD and republish the service.
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Yes!!!! that was it!
thank you so much everyone for all your help!0 -
Would only advice you to set the Clear Collection First in your Select Features activity to True. Then an existing selection is removed first.
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Good news Larisa, welcome to the learning curve Regards Ralph 0
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