Create a Pivot Table from a DataTable

Question

I am using C# winforms to create an application that needs to turn a datatable into a pivot table. I have the pivot table working fine from a SQL end, but creating it from a da

Answer 1

Maybe this will help you. It is in vb.net.

Public Function pivot_datatable(ByVal datatable_source As DataTable, ByVal datacolumn_rows As DataColumn(), ByVal datacolumn_columns As DataColumn, ByVal datacolumn_value As DataColumn) As DataTable
    Dim temp_datacolumn As DataColumn
    Dim current_datarow As DataRow
    Dim datarow_destination As DataRow = Nothing
    Dim current_column_name As String = ""
    Dim primary_key() As DataColumn = New DataColumn() {}
    Dim key_columns() As Object
    Dim newOrdinal As Integer
    Dim i As Integer
    Dim sort_string As String = ""

    Try
        pivot_datatable = New DataTable()

        For Each temp_datacolumn In datatable_source.Columns
            If temp_datacolumn.Ordinal <> datacolumn_columns.Ordinal AndAlso temp_datacolumn.Ordinal <> datacolumn_value.Ordinal Then
                array_insert(primary_key, pivot_datatable.Columns.Add(temp_datacolumn.ColumnName, temp_datacolumn.DataType))
                sort_string &= temp_datacolumn.ColumnName & " ASC, "
            End If
        Next
        pivot_datatable.PrimaryKey = primary_key

        For Each current_datarow In datatable_source.Rows ' Main Process to add values to pivot table
            current_column_name = current_datarow(datacolumn_columns.Ordinal).ToString
            If Not pivot_datatable.Columns.Contains(current_column_name) Then ' Column is new
                temp_datacolumn = pivot_datatable.Columns.Add(current_column_name, datacolumn_value.DataType)
                newOrdinal = temp_datacolumn.Ordinal
                For i = newOrdinal - 1 To datatable_source.Columns.Count - 2 Step -1
                    If temp_datacolumn.ColumnName.CompareTo(pivot_datatable.Columns(i).ColumnName) < 0 Then
                        newOrdinal = i
                    End If
                Next
                temp_datacolumn.SetOrdinal(newOrdinal)
            End If

            key_columns = New Object() {}
            For Each data_column As DataColumn In datacolumn_rows
                array_insert(key_columns, current_datarow(data_column.Ordinal).ToString)
            Next data_column
            datarow_destination = pivot_datatable.Rows.Find(key_columns)
            If datarow_destination Is Nothing Then ' New Row
                datarow_destination = pivot_datatable.NewRow()
                For Each temp_datacolumn In datatable_source.Columns
                    If temp_datacolumn.Ordinal <> datacolumn_columns.Ordinal AndAlso temp_datacolumn.Ordinal <> datacolumn_value.Ordinal Then
                        datarow_destination(temp_datacolumn.ColumnName) = current_datarow(temp_datacolumn.ColumnName)
                    End If
                Next
                pivot_datatable.Rows.Add(datarow_destination)
            End If
            datarow_destination(current_column_name) = current_datarow(datacolumn_value.Ordinal)
        Next

        Return sort_datatable(pivot_datatable, sort_string.Substring(0, sort_string.Length - 2))
    Catch ex As Exception
        Return Nothing
    End Try
End Function