Convert csv to xlsx in c#

Hi PowerShell,

I am facing some issues with convert csv to xlsx using c#.

If I am using PowerShell script without called through a C#. That is fine! But now I am written codes in powershell called through a C#.

here is my sample program code as below:

using (PowerShell PowerShellInstance = PowerShell.Create())
{

                string test = "Function Release-Ref ($ref) { \n" +
                    "([System.Runtime.InteropServices.Marshal]::ReleaseComObject([System.__ComObject]$ref) -gt 0) \n" +
                    "[System.GC]::Collect() \n" +
                    "[System.GC]::WaitForPendingFinalizers() \n" +
                    "} \n" +
                    "Function ConvertCSV-ToExcel { \n" +
                    "[CmdletBinding(SupportsShouldProcess = $True, ConfirmImpact = 'low', DefaultParameterSetName = 'file')] \n" +
                    "Param ([Parameter(ValueFromPipeline=$True, Position=0, Mandatory=$True, HelpMessage=\"Name of CSV/s to import\")] \n" +
                    "[ValidateNotNullOrEmpty()] \n" +
                    "[array]$inputfile, [Parameter( ValueFromPipeline=$False, Position=1, Mandatory=$True, HelpMessage=\"Name of excel file output\")] \n" +
                    "[ValidateNotNullOrEmpty()] \n" +
                    "[string]$output \n" +
                    ") \n" +
                    "Begin { \n" +
                    "[regex]$regex = \"^\\w\\:\\\" \n" +
                    "$count = ($inputfile.count -1) \n" +
                    "$excel = new-object -com excel.application \n" +
                    "$excel.DisplayAlerts = $False \n" +
                    "$excel.Visible = $False \n" +
                    "$workbook = $excel.workbooks.Add() \n" +
                    "$workbook.worksheets.add() \n" +
                    "$workbook.worksheets.add() \n" +
                    "$workbook.worksheets.Item(1).delete() \n" +
                    "$workbook.worksheets.Item(1).delete() \n" +
                    "$i = 1 \n" +
                    "} \n" +
                    "Process { \n" +
                    "ForEach ($input in $inputfile) { \n" +
                    "If ($i -gt 1) { $workbook.worksheets.Add() | Out-Null } \n" +
                    "$worksheet = $workbook.worksheets.Item(1) \n" +
                    "$worksheet.name = \"$((GCI $input).basename)\" \n" +
                    "If ($regex.ismatch($input)) { $tempcsv = $excel.Workbooks.Open($input)} \n" +
                    "ElseIf ($regex.ismatch(\"$($input.fullname)\")) { $tempcsv = $excel.Workbooks.Open(\"$($input.fullname)\") } \n" +
                    "Else {$tempcsv = $excel.Workbooks.Open(\"$($pwd)\\$input\")} \n" +
                    "$tempsheet = $tempcsv.Worksheets.Item(1) \n" +
                    "$tempSheet.UsedRange.Copy() | Out-Null \n" +
                    "$worksheet.Paste() \n" +
                    "$tempcsv.close() \n" +
                    "$range = $worksheet.UsedRange \n" +
                    "$range.EntireColumn.Autofit() | out-null \n" +
                    "$i++ \n" +
                    "}  \n" +
                    "}  \n" +
                    "End { \n" +
                    "$workbook.saveas(\"$pwd\\$output\") \n" +
                    "Write-Host -Fore Green \"File saved to $pwd\\$output\" \n" +
                    "$excel.quit()  \n" +
                    "$a = Release-Ref($range)\n" +
                    "}\n" +
                    "} \n" +
                    "ConvertCSV-ToExcel -inputfile .\\Demo.csv -output \"demo.xlsx\" ";


                PowerShellInstance.AddScript(test);
                PowerShellInstance.Invoke();

}

Where Demo.csv has data so i opened demo.xlsx and its empty after i build/Run.

Ref:
http://blogs.msdn.com/b/kebab/archive/2014/04/28/executing-powershell-scripts-from-c.aspx
https://gallery.technet.microsoft.com/scriptcenter/7c56c444-2476-4625-b1d9-821f30280e44/
http://learn-powershell.net/2010/09/04/converting-csv-file-or-files-into-an-excel-workbook/

Any Idea?

I am waiting for your response.

Thanks