das objekt mit null wert muss einen wert haben

[mred]

hello,

I have the following code and in the red line i recieve this message.
das objekt mit null wert muss einen wert haben
how to fix it?

If Flag2 = True Then
    Root.Expand()
    For i = 0 To RootNodes.Count - 1
        RootNodes.Item(i).Expand()
        Dim RootItemsfori = Root.Nodes.Item(i).Nodes
        For j = 0 To RootItemsfori.Count - 1
            RootItemsfori.Item(j).Expand()
            Dim RootItemsforj = Root.Nodes.Item(i).Nodes.Item(j).Nodes
            For k = 0 To RootItemsforj.Count - 1
                RootItemsforj.Item(k).Expand()
                Dim RootItemsforw = Root.Nodes.Item(i).Nodes.Item(j).Nodes.Item(k).Nodes
                For w = 0 To RootItemsforw.Count - 1
                    Dim cNI = TryCast(RootItemsforw.Item(w).Tag, RiskeySIITreeBuilder.NodeInfo)
                    If Not cNI.Key.UnterStArt.Value.ToString() Is Nothing Then
                        RootItemsforw.Item(w).Expand()
                    Else
                        Exit Sub
                    End If
                Next
            Next
        Next
    Next

[dday9]

FYI - Anytime you have Not {expression} Is Nothing, you can rewrite it to {expression} Is Not Nothing. It makes it easier to read in my opinion.

But if I understand it correctly the error message correctly (because it isn't in English and I'm relying on translate), you're attempting to access a value that doesn't exist. This is probably because one of the many chained properties/methods is returning nothing and you should only get the next property/method if the one before it isn't null. Maybe something like this:

cNI?.Key?.UnterStArt?.Value?.ToString()