#requires -version 2.0

Param (
[Parameter(Position=0)]
[ValidateSet("System","Application","Security","Directory Service","DNS Server")]
[string]$Log="System",
[ValidateRange(10,1000)]
[int]$Count=100,
[Parameter(Position=1,Mandatory=$True,
HelpMessage="What type of export file do you want to create? Valid choices are CSV, XML, CLIXML.")]
[ValidateSet("csv","xml","clixml" )]
[string]$Export,
[ValidateNotNullorEmpty()]
[string]$Path="C:\Work",
[string]$Computername=$env:Computername
)

Write-Verbose "Getting last $Count events from $log event log on $computername"
#base logname
$base="{0:yyyyMMdd}_{1}_{2}" -f (Get-date),$Computername,$Log

Try {
    $data=Get-EventLog -LogName $log -ComputerName $Computername -Newest $Count -errorAction Stop
}
Catch {
    Write-Warning "Failed to retrieve $log event log entries from $computername. $($_.Exception.Message)"
}

If ($data) {
    Write-Verbose "Exporting results to $($export.ToUpper())"
    Switch ($Export) {
        "csv" { $File=Join-path -Path $Path -ChildPath "$base.csv"
                $data | Export-Csv -Path $File  
              }
        "xml" {  $File=Join-path -Path $Path -ChildPath "$base.xml"
                ($data | ConvertTo-XML).Save($File)
               }
        "clixml" {$File= Join-path -Path $Path -ChildPath "$base.xml"
                $data | Export-Clixml -Path $File
                }
    } #switch

   Write-Verbose "Results exported to $File"

} #if $data