Convert xlsx to CSV without using Excel - powershell

Question

I get following error:
Cannot index into a null array.
At C:\tmp\Folder\excel\output\net45\test.ps1:14 char:1
+ $Data = $Reader.AsDataSet().Tables[0].Rows
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (:) [], RuntimeException
+ FullyQualifiedErrorId : NullArray
# Zero based index. The second row has index 1.
$StartRow = 2
# Input File
$InputFileName = "C:\tmp\Folder\excel\output\net20\test.xlsx"
# Output File
$OutputFileName = "C:\tmp\Folder\excel\output\net20\SomeFile.csv"
# Path to Excel.dll is saved (downloaded from http://exceldatareader.codeplex.com/)
$DllPath = "C:\tmp\Folder\excel\output\net45\Excel.4.5.dll"
[void]([Reflection.Assembly]::LoadFrom($DllPath))
$Stream = New-Object IO.FileStream($InputFileName, "Open", "Read")
$Reader = [Excel.ExcelReaderFactory]::CreateBinaryReader($Stream)
$Data = $Reader.AsDataSet().Tables[0].Rows
# Read the column names. Order should be preserved
$Columns = $Data[$StartRow].ItemArray
# Sort the remaining data into an object using the specified columns
$Data[$($StartRow + 1)..$($Data.Count - 1)] | % {
# Create an object
$Output = New-Object Object
# Read each column
for ($i = 0; $i -lt $Columns.Count; $i++) {
$Output | Add-Member NoteProperty $Columns[$i] $_.ItemArray[$i]
}
# Leave it in the output pipeline
$Output
} | Export-CSV $OutputFileName -NoType

Answer 1

You're calling the binary method (.xls) and using an Open XML format file (.xlsx). Try using [Excel.ExcelReaderFactory]::CreateOpenXmlReader($Stream) instead.
This works for me:
$DllPath = 'C:\Excel.DataReader.45\Excel.4.5.dll';
$FilePath = 'C:\Students.xlsx';
$FileMode = [System.IO.FileMode]::Open;
$FileAccess = [System.IO.FileAccess]::Read;
Add-Type -Path $DllPath;
$FileStream = New-Object -TypeName System.IO.FileStream $FilePath, $FileMode, $FileAccess;
$ExcelDataReader = [Excel.ExcelReaderFactory]::CreateOpenXmlReader($FileStream);
$ExcelDataReader.IsFirstRowAsColumnNames = $true;
$ExcelDataSet = $ExcelDataReader.AsDataSet();
$ExcelDataReader.Dispose();
$FileStream.Close();
$FileStream.Dispose();
$ExcelDataSet.Tables | Format-Table -AutoSize
If you're still having trouble, you might consider using the Microsoft.ACE.OLEDB.12.0 provider, which you install separately from Office. There's some doc here.

Answer 2

I've read this "Convert XLS to CSV on command line" and this "convert-xlsx-file-to-csv-using-batch" before in a similar doubt I have. Try too see if it helps.