How to relationship two DataTable and get Results in the third DataTable?

Question

Hello.

I want to get the filtered result in the third DataTable after relationship the two DataTables. Thank

        Dim dtParent As New DataTable
        Dim dtChild As New DataTable
        Dim dtResult As New DataTable
        dtParent.Columns.Add("filter")
        dtParent.Columns.Add("words")
        dtParent.Rows.Add({"a", "w1"})
        dtParent.Rows.Add({"b", "w2"})
        dtParent.Rows.Add({"c", "w3"})
        dtParent.Rows.Add({"k", "w4"})
        dtParent.Rows.Add({"m", "w5"})
        dtChild.Columns.Add("Filter")
        dtChild.Rows.Add("k")
        dtChild.Rows.Add("b")
        dtChild.Rows.Add("c")
        

tags: vb.net DataTable DataGridView

Answer 1

Hi @Mansour_Dalir ,

If you want to use DataRelation Class, you can refer to the following code.

        Dim dtset As New DataSet
        dtset.Tables.Add(dtParent)
        dtset.Tables.Add(dtChild)

        dtResult.Columns.Add("filter")
        dtResult.Columns.Add("words")

        Dim relation As New DataRelation("ParentChildRelation", dtParent.Columns("filter"), dtChild.Columns("Filter"))

        dtset.Relations.Add(relation)

        For Each childRow As DataRow In dtChild.Rows
            Dim filterValue As String = childRow("Filter").ToString()
            Dim parentRows As DataRow() = childRow.GetParentRows(relation)

            For Each parentRow As DataRow In parentRows
                dtResult.Rows.Add(parentRow("filter"), parentRow("words"))
            Next
        Next

Best Regards.

Jiachen Li

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