Nested while loop only runs once - powershell

Question

I am trying to use this script to add text to every file in a folder. It is working, but only on the first file in the folder. The for statement seems to be working because it is giving an accurate count of the files in the folder, but only modifying the first file. I feel like I am missing something stupid here.
$fullPath = "M:\BHX\DrillTeqConversion"
$reader = [System.IO.File]::OpenText("M:\BHX\DrillteqConversion.txt")
$lineNumberx = 25
function get200Files($path) {
$mprFiles = #(Get-ChildItem $path -include *.mpr -Recurse)
if ($mprFiles -ne $NULL) {
$mprFileCount = 0
For ($i = 0; $i -lt $mprFiles.Length; $i++) {
$mprFileCount += 1
$thisFile = $mprFiles[$i]
while($null -ne ($line = $reader.ReadLine())) {
$textToAdd = $line
$newLineToAdd = "`n"
$fileContent = Get-Content $thisFile
$fileContent[$lineNumberx-1] += $newLineToAdd
$fileContent[$lineNumberx-1] += $textToAdd
$fileContent | set-Content $thisFile
$lineNumberx = $lineNumberx + 1
}
}
Write-Host ("A total of " + $mprFileCount + " files were converted.")
}
}
get200Files $fullPath

Answer 1

[System.IO.File]::OpenText("M:\BHX\DrillteqConversion.txt") with ReadLine() only allows reading through a file once. So you cannot loop through the file endlessly without reopening it or using another strategy. Code samples below have been reduced for simplicity.
for ($i = 0; $i -lt $mprFiles.Length; $i++) {
# for loop code before while loop
$reader = [System.IO.File]::OpenText("M:\BHX\DrillteqConversion.txt")
while($null -ne ($line = $reader.ReadLine())) {
# while loop code
}
# After while loop but inside of For loop
$reader.Dispose()
$reader.Close()
}
You could make a new parameter for your function and pass that into OpenText() as well.
function get200Files($path,$FileToRead) {
for ($i = 0; $i -lt $mprFiles.Length; $i++) {
# for loop code before while loop
$reader = [System.IO.File]::OpenText($FileToRead)
while($null -ne ($line = $reader.ReadLine())) {
# while loop code
}
# After while loop but inside of For loop
$reader.Dispose()
$reader.Close()
}
}
$fullPath = "M:\BHX\DrillTeqConversion"
$ReaderPath = "M:\BHX\DrillteqConversion.txt"
get200Files $fullPath $ReaderPath