Looping Formula In Excel From VB.net Speed - vb.net

Question

Whole Code Explained:
I have this code that saves a txt file as a Microsoft Excel Comma Separated Values File (.csv) then opens a blank template excel file with a sheet named Graphs. It then copies the sheet with all the data from the csv file into the template excel file, renames it to "data" Then deletes the csv after close. The code then Inserts a chart in the "graph" sheet. Next it finds the total number of rows used and number of columns used for references for the ranges in the graphs and then for later formulas. This data is Acceleration from a accelerometer at a specific frequency. Therefor there is a lot of data, 8193 rows! The data lay out is top row labels (hz, Part1, 2...), Column A is frequencys, and all other cells from B2:whatever is accelerometer readings.
The Problem is it takes 83.22 seconds
to do the following loop, which inserts the average formula:
Do While i <= LastRow
'Assign Range To Take Average
CellLeft = wbtempXl.Worksheets("Data").Cells(i, 2)
CellRight = wbtempXl.Worksheets("Data").Cells(i, LastColumn)
AvgRange = wbtempXl.Worksheets("Data").Range(CellLeft, CellRight)
Average = appXL.WorksheetFunction.Average(AvgRange)
wbtempXl.Worksheets("Data").Cells(i, LastColumn + 1).Value = Average
i = i + 1
Loop
After this Average formula I am adding peak finding logic to find the peaks and troughs in the data, but this step alone takes a minute and a half. Is there a fast, better way of doing this? Looping formulas that is.
Note: I can not just have the formulas in the template. The test could include 12 parts or 100 parts. Each part has its own column and the frequency is in the rows of column A. The rest of the Rows is acceleration readings per frequency. Would post picture but not allowed to yet.
Full Code:
Public Sub btn_Do_Click(sender As Object, e As EventArgs) Handles btn_Do.Click
Dim FileTXT As String = cbo_FileList.Text
Dim folderpath As String = "C:\Users\aholiday\Desktop\Data Dump"
Dim txtpath As String = folderpath & "\" & FileTXT & ".txt"
Dim csvpath As String = "C:\Temp\" & FileTXT & ".csv"
Dim FinalFile As String = "C:\Users\aholiday\Desktop\Test"
Try
File.Copy(txtpath, csvpath)
Catch
MsgBox("Please Choose File")
Exit Sub
End Try
appXL = CreateObject("Excel.Application")
appXL.Visible = True
wbcsvXl = appXL.Workbooks.Open(csvpath)
wbtempXl = appXL.Workbooks.Open(FinalFile)
wbcsvXl.Worksheets(FileTXT).Copy(After:=wbtempXl.Worksheets("Graphs"))
wbtempXl.Worksheets(FileTXT).Name = ("Data")
'Close Objects
wbcsvXl.Close()
File.Delete(csvpath)
'Release Objects
wbcsvXl = Nothing
' Declare Varables
Dim Chart As Excel.Chart
Dim ChartXL As Excel.ChartObjects
Dim ThisChart As Excel.ChartObject
Dim SerCol As Excel.SeriesCollection
Dim Series As Excel.Series
Dim xRange As Excel.Range
Dim xCelltop As Excel.Range
Dim xCellBottom As Excel.Range
Dim yRange As Excel.Range
Dim yCelltop As Excel.Range
Dim yCellBottom As Excel.Range
Dim CellRight As Excel.Range
Dim CellLeft As Excel.Range
Dim AvgRange As Excel.Range
Dim Average As Double
Dim LastRow As Long
Dim LastColumn As Long
Dim i As Integer
' Set i integer
i = 2
'Make Chart
ChartXL = wbtempXl.Worksheets("Graphs").ChartObjects
ThisChart = ChartXL.Add(0, 0, 800, 400)
Chart = ThisChart.Chart
Chart.ChartType = Excel.XlChartType.xlXYScatterSmoothNoMarkers
With ThisChart.Chart
.HasTitle = True
.ChartTitle.Characters.Text = "RF Graph"
' X,Y title??????
End With
'Count Rows Used
'Find last Row Used
With wbtempXl.Worksheets("Data")
LastRow = .UsedRange.Rows.Count
End With
'Count Columns Used
'Find Last Column Used
With wbtempXl.Worksheets("Data")
LastColumn = .UsedRange.Columns.Count
End With
Do Until i > LastColumn
'Excel Chart X Axis Values
xCelltop = wbtempXl.Worksheets("Data").Cells(2, 1)
xCellBottom = wbtempXl.Worksheets("Data").Cells(LastRow, 1)
xRange = wbtempXl.Worksheets("Data").Range(xCelltop, xCellBottom)
'Excel Chart Y Axis Values
yCelltop = wbtempXl.Worksheets("Data").Cells(2, i)
yCellBottom = wbtempXl.Worksheets("Data").Cells(LastRow, i)
yRange = wbtempXl.Worksheets("Data").Range(yCelltop, yCellBottom)
'Label Part in Data Sheet
wbtempXl.Worksheets("Data").Cells(1, i).Value = ("Rotor " & i - 1)
'Add New Series to Chart
SerCol = Chart.SeriesCollection
Series = SerCol.NewSeries
'Rename and Assign Values
With Series
.Name = ("Rotor " & i - 1)
Series.XValues = xRange
Series.Values = yRange
End With
Chart.Refresh()
i = i + 1
Loop
'Add Average Column Label
wbtempXl.Worksheets("Data").Cells(1, LastColumn + 1).Value = "Average"
'Rest i integer
i = 2
Do While i <= LastRow
'Assign Range To Take Average
CellLeft = wbtempXl.Worksheets("Data").Cells(i, 2)
CellRight = wbtempXl.Worksheets("Data").Cells(i, LastColumn)
AvgRange = wbtempXl.Worksheets("Data").Range(CellLeft, CellRight)
Average = appXL.WorksheetFunction.Average(AvgRange)
wbtempXl.Worksheets("Data").Cells(i, LastColumn + 1).Value = Average
i = i + 1
Loop
'Release Objects
wbtempXl = Nothing
appXL = Nothing
GC.Collect()
Me.Close()
End Sub

Answer 1

I'd suggest you put formulas in the cells with code then convert to values if required:
With wbtempXl.Worksheets("Data")
formularange = .Range(.Cells(i, LastColumn + 1), .Cells(LastRow, LastColumn + 1))
End With
formularange.FormulaR1C1 = "=AVERAGE(RC2:RC[-1])"
formularange.Value2 = formularange.Value2