UI Demo -- Running InitAllApplications.xaml throws error "Object reference not set to an instance of an object"


i am working on the uidemo execution in RPA advanced course. I followed the guideline from the pdf. i got stuck in initallapplication.xaml. when i try to run it error is thrown “Object reference not set to an instance of an object”. Any help would be appreciated.

And also i run the main xaml getting error
Add key/value pair: Column ‘Value’ does not belong to table .

adding screenshots

Hi Jayavenkat,

First error, when you try to run InitAllApplications.xaml is because the in_Config argument is not set (it is Nothing or null) and you try to get a value from it - in_Config(“UiDemoPath”).ToString. This is the part that throws that “Object reference…” error. To fix this, to run only this workflow, you should create a unit test. Create a new workflow named InitAllApplications_Test.xaml and invoke there InitAllSettings.xaml and then InitAllApplications.xaml. Map the arguments as necessary (check how InitAllSettings.xaml is invoked in Init). Then you’ll get the Config dictionary that can be used as input argument for InitAllApplications.

Second error, when you try to run main is because your Config.xlsx file does not contains a column “Value” or because the Read Range in InitAllSettings.xaml does not have the “Add Headers” checked.

Please check both cases and let us know if problem is fixed or not.


Hi Silviu,

For the First error i created a test sequence by adding the initallsettings and initallapplications workflow and it works fine. it is able to open the application.

For the Main xaml execution still i face the same issue. Add headers is checked in initallsettings for the read range activity.
In config file under Assets tab, i have stored the application path as Robot Asset. In Assets tab there is no column named Value but when i change the Asset column to Value, i get error ‘Asset not defined’ . Please suggest.

Ok, if you store the application path as an Asset in Orchestrator, you need to put it in the Assets sheets, as you did. There the second column should be “Asset”, as in the picture you uploaded. It looks good.

Have you also added the asset in Orchestrator?
Can you attach your config file to this thread to take a look?

I have created the orchestrator asset.
Below are the config screenshots.

@Jayavenkat No You have added config file screenshot. Can you please add assets in Orchestrator. If you have already added please share the Screen Shot

And also MaximumRetry in config file should be 0. we have set the Retry to 2 in Orchestrator Queue

@Jayavenkat the configuration file looks good. Can you attach the entire project, with config file included, to this thread, or send it privately to me, so that I can check what’s the problem.

i figured that the following values not added to the config file.

After i added the above fields in the config settings the initialization happened. but now i face a different issue that clicking on login button in uidemo app doesnt do anything. i have enabled simulate click and activate checkboxes as per the walkthrough. now my config looks like this

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Hi Theepan,
am able to get the value from orchestrator asset. anyhow the initialization issue got resolved now am facing another issue with the uidemo app.

Did you run the dispatcher first to add queue items to Orchestrator. You can also check the Queue items in Orchestrator itself.

If Queue Items available It will get from Orchestrator to Demo App.

Can you please share or PM me you LoginUiDemo.xaml to rectify the issue

the queue items are available in the orchestrator. now i face this issue

System exception.The values provided for the root activity’s arguments did not satisfy the root activity’s requirements:
‘Process’: The following keys from the input dictionary do not map to arguments and must be removed: in_TransactionItem, in_Config. Please note that argument names are case sensitive.
Parameter name: rootArgumentValues at Source: System.Activities

Check in Dispatcher Add Queue Item information Column names

must be same in Assign Activity of Process.xaml


i think you are not using input arguments in_TransactionItem in Process.xaml

When i give the expression as you suggested. getting error.

@Jayavenkat can you check the type of in_TransactionItem Argument in Process.xaml. It should be QueueItem not a GenericValue

could you please tell me what is the argument type for in_config in the above screenshot

in_config is Dictionary<System.String, System.Object>

you can browse and find it

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Hi Theepan,

thanks a lot for your help.

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