I have read the relevant parts of the manual and experimented with all the TextBox related events including TextBoxFilterChar. However, I am unable to come up with a solid solution to satisfy all of the following rules.

1. Prevent paste into TextBox using Ctrl-V
2. Prevent paste into TextBox using Shift-Insert
3. Prevent typing of any char into TextBox

Thanks for any/all assistance.
I am also confused by some of the TextBoxKey events, such as in TextBoxKeyDown:

e.DoDefault's tooltip says "Determines whether to accept the key or not". But even with e.DoDefault set to False, the key is accepted.

        Private Sub ImbalancesGrid_TextBoxKeyDown(sender As Object, e As iGTextBoxKeyDownEventArgs) Handles ImbalancesGrid.TextBoxKeyDown
            e.DoDefault = False
        End Sub
"Determines whether to accept the key or not" in the context of the KeyDown event means disabling the action that is done from the KeyDown event, but for CTRL+V you should suppress the key press. Below is an example of how to disable CTRL+V in the fresh iGrid.NET v11 that provides the SuppressKeyPress property in the event args of the KeyDown event:

Private Sub IGrid1_TextBoxKeyDown(sender As Object, e As iGTextBoxKeyDownEventArgs) Handles IGrid1.TextBoxKeyDown
    If e.KeyValue = Keys.V And e.Modifiers = Keys.Control Then
        e.SuppressKeyPress = True
    End If
End Sub

You can do the same for SHIFT+INS and other keys.

Disabling any char input is implemented with the help of the TextBoxFilterChar event this way:

Private Sub IGrid1_TextBoxFilterChar(sender As Object, e As iGTextBoxFilterCharEventArgs) Handles IGrid1.TextBoxFilterChar
    e.Char = Chr(0)
End Sub

Prohibiting insertion may require other measures - for example, processing the textbox context menu with the paste command. If you cannot implement all this using the built-in iGrid tools but know how to do that in another WinForms control, you may think about implementing a custom editor inherited from the iGCellEditorBase class.