Column of checkboxes in a grid. Add-on crashes if we click where there is no box.

Hi, everybody

My previous post was oversimplified and did not clearly explain my problem.

See: How do we code for "NULL"?

So, I restate my problem more precisely.

Many thanks to all those who replied to my previous post.

Please see the attached picture which explains my problem.

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The relevant (simplified) codes are shown below:

Grid.Columns.Item("Mark as Completed").Type =

SAPbouiCOM.BoGridColumnType.gct_CheckBox

RemoveHandler Grid.Columns.Item("Mark as Completed").PressedBefore,

AddressOf OnBeforeMarkasCompletedPressed

AddHandler Grid.Columns.Item("Mark as Completed").PressedBefore,

AddressOf OnBeforeMarkasCompletedPressed

----------------------------------------------------------------

PrivateSub OnBeforeMarkasCompletedPressed(ByVal Source AsObject,

ByVal pVal As SAPbouiCOM.SBOItemEventArg, ByRef Bubble AsBoolean)

        If Grid.DataTable.GetValue("PO Status", SelectedRow) = "Closed"Then

SBO_Application.MessageBox("CLOSED")

Bubble = False

        ElseIf Grid.DataTable.GetValue("PO Status", SelectedRow) = "-"Then

SBO_Application.MessageBox("MINUS")

Bubble = False

            'ElseIf Grid.DataTable.GetValue("PO Status", SelectedRow) Is Nothing Then

            ' SBO_Application.MessageBox("BLANK")

            '    Bubble = False

        EndIf

    EndSub

---------------------------------------------------------

Here is the Error Message:

Thanks

Leon