PREGUNTAS CONTESTADAS - ASP.NET

Private Shared Function SaveAsCSV(ByVal selectCommand As SqlClient.SqlCommand, ByVal FileCSV As

 System.IO.StreamWriter, ByVal ColumnsExcluded() As String) As Integer

            Dim Reader As SqlClient.SqlDataReader

            Dim dtSchema As DataTable

            Dim rowSchema As DataRow

            Dim i, j, IndexColumn As Short

            Dim ArrayIndex As New ArrayList

            Dim ArrayNames As New ArrayList

            Dim FieldIndex() As Short

            Dim nRecords As Integer

            Dim ColumnName As String

            Dim StrLine, StrValue, StrFormat As String

            Dim utf8 As New System.Text.UTF8Encoding



            Const FieldSeparator As String = ","



            System.Threading.Thread.CurrentThread.CurrentCulture = CSVCulture()



            For i = 0 To ColumnsExcluded.Length - 1

                ColumnsExcluded(i) = Trim(ColumnsExcluded(i)).ToLower()

            Next



            ' execute select command

            Reader = selectCommand.ExecuteReader()

            dtSchema = Reader.GetSchemaTable()



            ' included field indexes

            For i = 0 To dtSchema.Rows.Count - 1

                rowSchema = dtSchema.Rows(i)

                ColumnName = rowSchema("ColumnName")

                If [Array].IndexOf(ColumnsExcluded, ColumnName.ToLower()) < 0 Then

                    ArrayIndex.Add(i)

                End If

            Next

            FieldIndex = ArrayIndex.ToArray(GetType(Short))



            ' ... Formato de exportacion por campo

            Dim StrColumns() As String = [Array].CreateInstance(GetType(String), dtSchema.Rows.Count)

            Dim CSVFormats() As String = [Array].CreateInstance(GetType(String), dtSchema.Rows.Count)

            For j = 0 To FieldIndex.Length - 1

                IndexColumn = FieldIndex(j)

                rowSchema = dtSchema.Rows(IndexColumn)

                ArrayNames.Add(rowSchema("ColumnName"))

                Select Case System.Type.GetTypeCode(rowSchema("DataType"))

                    Case TypeCode.String, TypeCode.Char

                        StrFormat = """{0}"""

                    Case TypeCode.DateTime

                        StrFormat = "{0:d}"

                    Case TypeCode.Int16, TypeCode.Int32, TypeCode.Int64, TypeCode.Byte, TypeCode.UInt16, TypeCode.UInt32, TypeCode.UInt64

                        StrFormat = "{0}"

                    Case TypeCode.Decimal, TypeCode.Double, TypeCode.Single

                        StrFormat = "{0}"

                    Case TypeCode.Boolean

                        StrFormat = "{0}"

                    Case Else

                        StrFormat = "{0}"

                End Select

                CSVFormats(IndexColumn) = StrFormat

            Next



            ' exportar nombres de columnas

            FileCSV.WriteLine([String].Join(",", ArrayNames.ToArray(GetType(String))))



            ' exportar datos

            While Reader.Read()

                StrLine = ""

                For j = 0 To FieldIndex.Length - 1

                    IndexColumn = FieldIndex(j)

                    If Not Reader.IsDBNull(IndexColumn) Then

                        StrValue = String.Format(CSVFormats(IndexColumn), Reader.GetValue(IndexColumn))

                        StrLine = StrLine & StrValue

                    End If

                    StrLine = StrLine & FieldSeparator

                Next

                FileCSV.WriteLine(StrLine)

                nRecords += 1

            End While



            Reader.Close()



            ' exporttación finalizada

            Return nRecords



        End Function



        ''' 


        ''' Retorna información cultural específica para exportación en formato CSV

        ''' 

        ''' -----------------------------------------------------------------------------

        Private Shared Function CSVCulture() As System.Globalization.CultureInfo

            Dim CultureInfo As New System.Globalization.CultureInfo("es-CO")

            CultureInfo.NumberFormat.CurrencySymbol = "$"

            CultureInfo.NumberFormat.CurrencyDecimalSeparator = "."

            CultureInfo.NumberFormat.CurrencyGroupSeparator = ","

            CultureInfo.NumberFormat.CurrencyDecimalDigits = 2

            CultureInfo.NumberFormat.NumberDecimalSeparator = "."

            CultureInfo.NumberFormat.NumberGroupSeparator = ","

            CultureInfo.NumberFormat.NumberDecimalDigits = 2

            CultureInfo.NumberFormat.PercentDecimalSeparator = "."

            CultureInfo.NumberFormat.PercentGroupSeparator = ","

            Return CultureInfo

        End Function