Exception has been thrown by the target of an invocation - vb.net - vb.net

Question

I have an issue where I am receiving the error, "Exception has been thrown by the target of an invocation. I have the new keyword in place. I made sure the ReportsData_Employee.COATSEndAssignmentDataTable existed.
Imports System.Windows.Forms
Imports Advance.Extensions.Reporting
Imports CrystalDecisions.Shared
Imports Advance.Common.Reporting
Imports System.IO
Public Class Activity_EndAssignmentTool
ReadOnly _dt As New DataTable
Dim _dts As New DataTable
Dim _bldts As New DataTable
Dim _xml_file_name_creation As String
'// This is the line that is causing the error ============
ReadOnly _xml_datatable As ReportsData_Employee.COATSEndAssignmentDataTable = New ReportsData_Employee.COATSEndAssignmentDataTable()
'//^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
======================================================================================
System.Reflection.TargetInvocationException was caught
HResult=-2146232828
Message=Exception has been thrown by the target of an invocation.
Source=mscorlib
StackTrace:
at System.RuntimeTypeHandle.CreateInstance(RuntimeType type, Boolean publicOnly, Boolean noCheck, Boolean& canBeCached, RuntimeMethodHandleInternal& ctor, Boolean& bNeedSecurityCheck)
at System.RuntimeType.CreateInstanceSlow(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache, StackCrawlMark& stackMark)
at System.RuntimeType.CreateInstanceDefaultCtor(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache, StackCrawlMark& stackMark)
at System.Activator.CreateInstance(Type type, Boolean nonPublic)
at System.RuntimeType.CreateInstanceImpl(BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes, StackCrawlMark& stackMark)
at System.Activator.CreateInstance(Type type, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes)
at System.Reflection.Assembly.CreateInstance(String typeName, Boolean ignoreCase, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes)
at System.Reflection.Assembly.CreateInstance(String typeName)
at Advance.Extensions.Activities.Activity_Form.GetActivityForm(String className) in C:\Users\JJanssen\Documents\Visual Studio 2010\Projects\Legacy\Advance Extensions\advance.extensions.activities\Forms\Activity_Form.vb:line 126
at Advance.Extensions.Activities.Activity_Form.SetActivityClass() in C:\Users\JJanssen\Documents\Visual Studio 2010\Projects\Legacy\Advance Extensions\advance.extensions.activities\Forms\Activity_Form.vb:line 60
InnerException: System.NullReferenceException
HResult=-2147467261
Message=Object reference not set to an instance of an object.
Source=Advance.Extensions.Activities
StackTrace:
at Advance.Extensions.Activities.Activity_EndAssignmentTool.InitializeComponent() in C:\Users\JJanssen\Documents\Visual Studio 2010\Projects\Legacy\Advance Extensions\advance.extensions.activities\Activity_Forms\Activity_EndAssignmentTool.Designer.vb:line 479
at Advance.Extensions.Activities.Activity_EndAssignmentTool..ctor() in C:\Users\JJanssen\Documents\Visual Studio 2010\Projects\Legacy\Advance Extensions\advance.extensions.activities\Activity_Forms\Activity_EndAssignmentTool.vb:line 12
InnerException:
Can someone name some other reasons why I could be getting this error? I have looked at multiple links but a lot of the answers don't apply in my situation.
"Exception has been thrown by the target of an invocation" error (mscorlib)
FYI I have tried ReadOnly _xml_datatable as New ReportsData_Employee.COATSEndASsignmentDataTable() and there was still an issue.
Any help is appreciated. Let me know if there is any other information you need.
Thanks.

Answer 1

You haven't initialized object properly. Here...
ReadOnly _xml_datatable As ReportsData_Employee.COATSEndAssignmentDataTable = New ReportsData_Employee.COATSEndAssignmentDataTable()
Should be
Private ReadOnly _xml_datatable As New ReportsData_Employee.COATSEndAssignmentDataTable()
Your real issue is
InnerException: System.NullReferenceException
HResult=-2147467261
Message=Object reference not set to an instance of an object.
Source=Advance.Extensions.Activities
You need to look into constructor of COATSEndAssignmentDataTable. you have NullReferenceException in there. These two lines tell you exact location
at Advance.Extensions.Activities.Activity_EndAssignmentTool.InitializeComponent()
in C:\Users\JJanssen\Documents\Visual Studio 2010\Projects\Legacy\Advance Extensions\advance.extensions.activities\Activity_Forms\Activity_EndAssignmentTool.Designer.vb:line 479
at Advance.Extensions.Activities.Activity_EndAssignmentTool..ctor()
in C:\Users\JJanssen\Documents\Visual Studio 2010\Projects\Legacy\Advance Extensions\advance.extensions.activities\Activity_Forms\Activity_EndAssignmentTool.vb:line 12