How to set data from DataTable to TreeView

Question

If possible, first convert it to a multidimensional array through 'LINQ 'and then set it to TreeView L=LEVEL .Thank you with all due respect

   Dim MyDataTable As New DataTable
        MyDataTable.Columns.Add("A")
        MyDataTable.Columns.Add("B")
        MyDataTable.Columns.Add("C")
        MyDataTable.Rows.Add({"a", "aL2_1", "aL3_1"})
        MyDataTable.Rows.Add({"b", "bL2_1", "bL3_2"})
        MyDataTable.Rows.Add({"a", "aL2_1", "aL3_2"})
        MyDataTable.Rows.Add({"a", "aL2_2", "aL3_1"})
        MyDataTable.Rows.Add({"b", "bL2_1", "bL3_1"})
        MyDataTable.Rows.Add({"c", "cL2_1", "cL3_1"})

Answer 1

Hi @Mansour_Dalir ,

You can refer to the following code.

        Dim array = (From row In MyDataTable.AsEnumerable()
                     Select row.ItemArray).ToArray()

        For Each item In array
            Dim parentNode As TreeNode = Nothing
            For i = 0 To item.Length - 1
                Dim value = item(i).ToString()
                Dim node As TreeNode = Nothing

                If parentNode IsNot Nothing Then
                    node = parentNode.Nodes.Cast(Of TreeNode)() _
                        .FirstOrDefault(Function(n) n.Text = value)
                Else
                    node = TreeView1.Nodes.Cast(Of TreeNode)() _
                        .FirstOrDefault(Function(n) n.Text = value)
                End If

                If node Is Nothing Then
                    node = New TreeNode(value)
                    If parentNode IsNot Nothing Then
                        parentNode.Nodes.Add(node)
                    Else
                        TreeView1.Nodes.Add(node)
                    End If
                End If

                parentNode = node
            Next
        Next

Best Regards.

Jiachen Li

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