List operation getting Null exception

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Hello Everyone,   I am trying to perform List operation and I am getting the below error. Even when I tried to expand the under variable during debugging mode I am facing the same issue.    System.NullReferenceException: Object reference not set to an instance of an object.    at Mendix.Modeler.Debugger.Runtime.Values.ObjectValue.get_Value() in C:\Users\Autobuild\workspace\AppStudio4.0-Build\modeler\Mendix.Modeler.Debugger\Runtime\Values\ObjectValue.cs:line 30    at Mendix.Modeler.Debugger.ToolWindows.Variables.VariableTreeItemViewModel.Init(INode`1 node, Boolean isRootNode) in C:\Users\Autobuild\workspace\AppStudio4.0-Build\modeler\Mendix.Modeler.Debugger\ToolWindows\Variables\VariableTreeItemViewModel.cs:line 47    at Mendix.Modeler.Controls.Tree.TreeItemHandler`2.DoSyncItemsWithNewNodes(TreeItemCollection existingItems, IList`1 newNodes, Boolean rootNodes) in C:\Users\Autobuild\workspace\AppStudio4.0-Build\modeler\Mendix.Modeler.Controls\Tree\ViewModels\TreeItemHandler.cs:line 68    at Mendix.Modeler.Controls.Tree.TreeItemHandler`2.DoSyncItemsWithNewNodes(TreeItemCollection existingItems, IList`1 newNodes, Boolean rootNodes) in C:\Users\Autobuild\workspace\AppStudio4.0-Build\modeler\Mendix.Modeler.Controls\Tree\ViewModels\TreeItemHandler.cs:line 90    at Mendix.Modeler.Controls.Tree.TreeViewModel`2.<ExpandCollapse>b__94_0() in C:\Users\Autobuild\workspace\AppStudio4.0-Build\modeler\Mendix.Modeler.Controls\Tree\ViewModels\TreeViewModel.cs:line 277    at Mendix.Modeler.Controls.Tree.TreeViewModel`2.ExpandCollapse(ITreeItemViewModel item, Boolean expand) in C:\Users\Autobuild\workspace\AppStudio4.0-Build\modeler\Mendix.Modeler.Controls\Tree\ViewModels\TreeViewModel.cs:line 275    at Mendix.Modeler.Controls.Tree.TreeControl`2.OnExpanded(Object sender, TreeGridViewItemEventArgs e) in C:\Users\Autobuild\workspace\AppStudio4.0-Build\modeler\Mendix.Modeler.Controls\Tree\Views\TreeControl.cs:line 169    at Eto.PropertyStore.TriggerEvent[T](Object key, Object sender, T args)    at Eto.Forms.TreeGridView.OnExpanded(TreeGridViewItemEventArgs e)    at Eto.Forms.TreeGridView.Callback.OnExpanded(TreeGridView widget, TreeGridViewItemEventArgs e)    at Eto.Wpf.Forms.Controls.TreeGridViewHandler.<AttachEvent>b__5_3(Object sender, TreeGridViewItemEventArgs e)    at Eto.CustomControls.TreeController.OnExpanded(TreeGridViewItemEventArgs e)    at Eto.CustomControls.TreeController.ExpandRow(Int32 row)    at Eto.Wpf.CustomControls.TreeGridView.TreeToggleButton.ToggleExpandCollapse()    at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)    at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)
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2 answers
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hi Karthikeyan Annadurai,

             your trying to perform list operation ,it will pass on to next activity if the list is retrieving Properly .

             I think your retrieving the list by association . if that is the case ,their is no object from which is to be retrived.so it is showing                 error message

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Hi Karthikeyan,

 

The error message looks like a bug in Mendix Studio Pro to me.

I notice you are running versieon 9.12.2, which is an outdated version. I suggest updating to one of the MTS or LTS versions and then try again. https://marketplace.mendix.com/link/studiopro/ 

 

I hope this helps.

 

answered