Are you looking for something like this
$controllerdetails = Get-Content "c:\vinith\desktop\controllerdetails.csv"
foreach ($control in $controllerdetails)
{
if (($global:CurrentNaController).name -match $control.filername)
{
New-NaVol -Name $control.volumename ....(continued syntax)...
}
else
{
Connect-NaController $control.filername ...(continued syntax)......
New-NaVol -Name $control.volumename ..(continued syntax).....
}
}