Visual Basic.NET - Exportar en forma rapida GridView a excel

Private Sub btn_expo_pend_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn_expo_pend.Click

        Dim app As Microsoft.Office.Interop.Excel._Application = New Microsoft.Office.Interop.Excel.Application()

        Dim workbook As Microsoft.Office.Interop.Excel._Workbook = app.Workbooks.Add(Type.Missing)

        Dim worksheet As Microsoft.Office.Interop.Excel._Worksheet '= Nothing.worksheet = workbook.Sheets("Hoja1")

        worksheet = workbook.ActiveSheet

        For i As Integer = 1 To dgv_pend_mensa.Columns.Count

            worksheet.Cells(1, i) = dgv_pend_mensa.Columns(i - 1).HeaderText

        Next

        For i As Integer = 0 To dgv_pend_mensa.Rows.Count - 1

            For j As Integer = 0 To dgv_pend_mensa.Columns.Count - 1

                worksheet.Cells(i + 2, j + 1) = dgv_pend_mensa.Rows(i).Cells(j).Value.ToString()

            Next

        Next

        worksheet.PageSetup.Zoom = 85

        worksheet.PageSetup.Orientation = Microsoft.Office.Interop.Excel.XlPageOrientation.xlLandscape

        worksheet.PageSetup.LeftMargin = 0

        worksheet.PageSetup.RightMargin = 0

        worksheet.Cells.Font.Size = 9

        worksheet.Rows.Item(1).Font.Bold = 1

        worksheet.Columns.AutoFit()

        worksheet.Columns.HorizontalAlignment = 2

        worksheet.PageSetup.CenterHeader = "Pendientes Mensajero:" & cmb_mensa_pend.Text & "FECHA " & Date.Today & " "

        worksheet.PageSetup.CenterFooter = "Pendientes =" & lbl_cod_pen.Text & ""

        worksheet.PageSetup.PrintTitleRows = "$1:$1"

        worksheet.PageSetup.PrintTitleColumns = "$A:$H"

        app.Visible = True

        GC.Collect()

        txt_cod_pend.Text = ""

        cmb_mensa_pend.Text = ""

        dgv_pend_mensa.Rows.Clear()

    End Sub

Try

            Dim ds As New DataSet

            Dim cmd As New OleDb.OleDbCommand("SELECT SUCURSALES.nomsucursal as [SUCURSAL], EMPLEADOS.cargo AS [CARGO], EMPLEADOS.Idempleado AS [ID_EMPLEADO], EMPLEADOS.nomempleado AS [NOM_EMPLEADO],distritos.nomdistrito as [DISTRITO], EMPLEADOS.direccion AS [DIRECCION], EMPLEADOS.dni AS [DNI], EMPLEADOS.telefono AS [FONO], EMPLEADOS.activo AS [ACT] FROM DISTRITOS ,SUCURSALES,EMPLEADOS WHERE SUCURSALES.Idsucursal = EMPLEADOS.idsucursal AND  DISTRITOS.Iddistrito = EMPLEADOS.iddistrito and sucursales.nomsucursal like '%" & cmbsucursal.Text & "' and EMPLEADOS.nomEMPLEADO like '%" & txtnomempleado.Text.Trim & "%' AND distritos.nomdistrito like '%" & cmbdistrito.Text.Trim & "' AND empleados.activo like '%" & cmbactivo.Text & "' and empleados.cargo like '%" & TXTidcargo.Text & "'", Cn)

            Dim da As New OleDb.OleDbDataAdapter(cmd)

            da.Fill(ds, "Items")

            dtSource = ds.Tables("Items")

            DGVempleado.DataSource = ds.Tables("Items")

        Catch ex As Exception

            If Cn.State = ConnectionState.Open Then Cn.Close()

            MsgBox(ex.Message)

        End Try

If DGVcliente.RowCount > 0 Then

                Dim save As New SaveFileDialog

                save.Filter = "ARCHIVO XML (*.xml)|*.xml"

                save.FileName = "EMPLEADOS" & " " & Now.Day & "-" & Now.Month & "-" & Now.Year & ".xml"

                If save.ShowDialog = Windows.Forms.DialogResult.OK Then

                    'If Not IO.File.Exists(save.FileName) Then

                    Dim fs As System.IO.FileStream

                    Dim xtw As System.Xml.XmlTextWriter

                    dtSource.TableName = "items"

                    fs = New System.IO.FileStream(save.FileName, IO.FileMode.Create)

                    xtw = New System.Xml.XmlTextWriter(fs, System.Text.Encoding.Unicode)

                    xtw.WriteProcessingInstruction("xml", "version='1.0'")

                    xtw.WriteProcessingInstruction("mso-application", "progid='Excel.Sheet'")

                    dtSource.WriteXml(xtw)

                    xtw.Close()

                    MsgBox("SE EXPORTO CORRECTAMENTE")

                End If

            Else

                MsgBox("NO HAY DATOS QUE EXPORTAR", MsgBoxStyle.Critical, "VERIFICAR")

                Exit Sub

            End If

Try

		Dim sql1 As String = "SELECT funes.folio,funes.notif as Codigo,funes.ingreso as Fecha_Entrega,funes.rebaje as Rebaje," _

							& "tabla.detalle as Mensajero,received.rcv_razon as Razon_Social,received.rcv_direcc as Direccion," _

							& "received.rcv_comuna as Comuna,received.rcv_rutemp As Rut_Empresa,funes.proceso,procesos.pro_glo As Glosa," _

							& "FUNES.ESTADO AS ESTADO,funes.termino as Fecha_termino, received.rcv_fecent as Fecha_Entrega_Isapre," _

							& "funes.rechazo as Rechazo, funes.notifdev as MensajeroDevolucion, funes.diasdev as DiasDevolucion," _

						& "funes.papeleta as Papeleta, funes.f_rendicion as Rendicion, funes.numrend as NumeroRendicion," _

						& "funes.fecfun as FechaFun, received.rcv_tipfun as TipoFun, FUNES.ANO, FUNES.MES, received.rcv_ano," _

						& "received.rcv_mes, funes.isapre, received.rcv_rutafi, received.rcv_nomafi, funes.carta FROM tabla INNER JOIN" _

						& "(((funes INNER JOIN pend ON funes.folio = pend.folio)INNER JOIN received on received.rcv_folio = pend.folio)" _

					& "INNER JOIN procesos ON procesos.pro_num = funes.proceso)ON tabla.codigo = funes.notif and funes.posta='1'"

		mensaje.ProgressBar1.Increment(10)

		Dim da2 As New OleDbDataAdapter(sql1, cnn)

		Dim ds2 As New DataSet

		da2.Fill(ds2, sql1)

		Dim dt2 As DataTable = ds2.Tables(sql1)

		dgv_consulta.DataSource = dt2

	Catch ex As Exception

		MessageBox.Show(ex.Message)

	End Try

	mensaje.Close()

End Using

Try

            Dim ds As New DataSet

            Dim cmd As New OleDb.OleDbCommand("SELECT funes.folio,funes.notif as Codigo,funes.ingreso as Fecha_Entrega,funes.rebaje as Rebaje," _

							& "tabla.detalle as Mensajero,received.rcv_razon as Razon_Social,received.rcv_direcc as Direccion," _

							& "received.rcv_comuna as Comuna,received.rcv_rutemp As Rut_Empresa,funes.proceso,procesos.pro_glo As Glosa," _

							& "FUNES.ESTADO AS ESTADO,funes.termino as Fecha_termino, received.rcv_fecent as Fecha_Entrega_Isapre," _

							& "funes.rechazo as Rechazo, funes.notifdev as MensajeroDevolucion, funes.diasdev as DiasDevolucion," _

						& "funes.papeleta as Papeleta, funes.f_rendicion as Rendicion, funes.numrend as NumeroRendicion," _

						& "funes.fecfun as FechaFun, received.rcv_tipfun as TipoFun, FUNES.ANO, FUNES.MES, received.rcv_ano," _

						& "received.rcv_mes, funes.isapre, received.rcv_rutafi, received.rcv_nomafi, funes.carta FROM tabla INNER JOIN" _

						& "(((funes INNER JOIN pend ON funes.folio = pend.folio)INNER JOIN received on received.rcv_folio = pend.folio)" _

					& "INNER JOIN procesos ON procesos.pro_num = funes.proceso)ON tabla.codigo = funes.notif and funes.posta='1'", Cn)

            Dim da As New OleDb.OleDbDataAdapter(cmd)

            da.Fill(ds, "Items")

            dtSource = ds.Tables("Items")

            DGVempleado.DataSource = ds.Tables("Items")

        Catch ex As Exception

            If Cn.State = ConnectionState.Open Then Cn.Close()

            MsgBox(ex.Message)

        End Try

'Tengo un formulario con un datagrid llamado DtGrTabla

Dim dtTabla as new DataTable

'Aquí pongo mi código para abrir mi datatable

DtGrTabla.DataSource = DtTabla

'Abro una hoja de excel

Dim HojaExcel As Excel.Application

Dim exBook As Excel.Workbook

HojaExcel = New Excel.Application

exBook = HojaExcel.Workbooks.Add

HojaExcel.Visible = False

'Selecciono todo el datagrid y copio su contenido al portapapeles

DtGrTabla.SelectAll()

Dim dataObj As DataObject = DtGrTabla.GetClipboardContent

If Not IsNothing(dataObj) Then

    Clipboard.SetDataObject(dataObj)

End If

'Selecciono la celda desde la cual quiero copiar y pego

HojaExcel.Range("A1").Select()

HojaExcel.ActiveSheet.Paste

'Y ya sea que guardes el excel o que lo abras

HojaExcel.Visible = True