This function reads a CSV file of 15MB and copies its content into a sheet in about 3 secs. What is probably taking a lot of time in your code is the fact that you copy data cell by cell instead of putting the whole content at once.
Option Explicit
Public Sub test()
copyDataFromCsvFileToSheet "C:\temp\test.csv", ",", "Sheet1"
End Sub
Private Sub copyDataFromCsvFileToSheet(parFileName As String, parDelimiter As String, parSheetName As String)
Dim data As Variant
data = getDataFromFile(parFileName, parDelimiter)
If Not isArrayEmpty(data) Then
With Sheets(parSheetName)
.Cells.ClearContents
.Cells(1, 1).Resize(UBound(data, 1), UBound(data, 2)) = data
End With
End If
End Sub
Public Function isArrayEmpty(parArray As Variant) As Boolean
'Returns false if not an array or dynamic array that has not been initialised (ReDim) or has been erased (Erase)
If IsArray(parArray) = False Then isArrayEmpty = True
On Error Resume Next
If UBound(parArray) < LBound(parArray) Then isArrayEmpty = True: Exit Function Else: isArrayEmpty = False
End Function
Private Function getDataFromFile(parFileName As String, parDelimiter As String, Optional parExcludeCharacter As String = "") As Variant
'parFileName is supposed to be a delimited file (csv...)
'parDelimiter is the delimiter, "," for example in a comma delimited file
'Returns an empty array if file is empty or can't be opened
'number of columns based on the line with the largest number of columns, not on the first line
'parExcludeCharacter: sometimes csv files have quotes around strings: "XXX" - if parExcludeCharacter = """" then removes the quotes
Dim locLinesList() As Variant
Dim locData As Variant
Dim i As Long
Dim j As Long
Dim locNumRows As Long
Dim locNumCols As Long
Dim fso As Variant
Dim ts As Variant
Const REDIM_STEP = 10000
Set fso = CreateObject("Scripting.FileSystemObject")
On Error GoTo error_open_file
Set ts = fso.OpenTextFile(parFileName)
On Error GoTo unhandled_error
'Counts the number of lines and the largest number of columns
ReDim locLinesList(1 To 1) As Variant
i = 0
Do While Not ts.AtEndOfStream
If i Mod REDIM_STEP = 0 Then
ReDim Preserve locLinesList(1 To UBound(locLinesList, 1) + REDIM_STEP) As Variant
End If
locLinesList(i + 1) = Split(ts.ReadLine, parDelimiter)
j = UBound(locLinesList(i + 1), 1) 'number of columns
If locNumCols < j Then locNumCols = j
i = i + 1
Loop
ts.Close
locNumRows = i
If locNumRows = 0 Then Exit Function 'Empty file
ReDim locData(1 To locNumRows, 1 To locNumCols + 1) As Variant
'Copies the file into an array
If parExcludeCharacter <> "" Then
For i = 1 To locNumRows
For j = 0 To UBound(locLinesList(i), 1)
If Left(locLinesList(i)(j), 1) = parExcludeCharacter Then
If Right(locLinesList(i)(j), 1) = parExcludeCharacter Then
locLinesList(i)(j) = Mid(locLinesList(i)(j), 2, Len(locLinesList(i)(j)) - 2) 'If locTempArray = "", Mid returns ""
Else
locLinesList(i)(j) = Right(locLinesList(i)(j), Len(locLinesList(i)(j)) - 1)
End If
ElseIf Right(locLinesList(i)(j), 1) = parExcludeCharacter Then
locLinesList(i)(j) = Left(locLinesList(i)(j), Len(locLinesList(i)(j)) - 1)
End If
locData(i, j + 1) = locLinesList(i)(j)
Next j
Next i
Else
For i = 1 To locNumRows
For j = 0 To UBound(locLinesList(i), 1)
locData(i, j + 1) = locLinesList(i)(j)
Next j
Next i
End If
getDataFromFile = locData
Exit Function
error_open_file: 'returns empty variant
unhandled_error: 'returns empty variant
End Function