get full string before first second third etc. split - vb.net

Question

I have a file location and I need to check if it exists.
The way I wan't to do it is like this:
Dim route As String = ("C:\testing1\testing2\testing3\testing4\testing5\TEXTBESTAND.txt")
If System.IO.File.Exists(route) Then
MsgBox("BESTAAT HET WERKT!")
Else
Dim subroute() As String = route.Split("\"c)
Dim counting As Integer = route.Split("\"c).Length - 1
For count2 As Integer = 0 To counting - 1
Dim firstbackslash As Integer = route.IndexOf("\")
Dim backslash As Integer = route.IndexOf("\", firstbackslash + 1)
Dim firstPart As String = route.Substring(0, backslash)
MsgBox(firstPart)
Next
What I try to accomplisch is that I fist check if folder "C:" exists then "C:\testing1" then "C:\testing1\testing2" etc.
But I cant find something like this on the internet nor with some messing around...

Answer 1

Here is an algorithm that that will give you all the paths starting from the root and building up to the final path including the filename. You can use this to check for each folder and create them as you go if they don't exist:
Sub Main()
Dim route As String = ("C:\testing1\testing2\testing3\testing4\testing5\TEXTBESTAND.txt")
Dim fi As New System.IO.FileInfo(route)
If Not fi.Exists Then
Dim fileName As String = Path.GetFileName(route)
Dim di As DirectoryInfo = fi.Directory
Dim pathStack As New Stack(Of String)()
pathStack.Push(di.Name)
While Not IsNothing(di.Parent)
di = di.Parent
pathStack.Push(di.Name)
End While
Dim curPath As String = ""
While pathStack.Count > 0
curPath = Path.Combine(curPath, pathStack.Pop)
' ... do something with "curPath" in here ...
' ... like check for existence and create it ...
Console.WriteLine(curPath)
End While
curPath = Path.Combine(curPath, fileName)
' ... do something with "curPath" in here ...
' ... this is the full path including the file on the end ...
Console.WriteLine(curPath)
End If
Console.Write("Press Enter to quit...")
Console.ReadLine()
End Sub
Output:
C:\
C:\testing1
C:\testing1\testing2
C:\testing1\testing2\testing3
C:\testing1\testing2\testing3\testing4
C:\testing1\testing2\testing3\testing4\testing5
C:\testing1\testing2\testing3\testing4\testing5\TEXTBESTAND.txt
Press Enter to quit...

Answer 2

Don't use string mnaipulation to work with file or folder paths. use the Path class.
One option:
Private Function GetExistingSubPath(fullPath As String) As String
If Directory.Exists(fullPath) OrElse File.Exists(fullPath) Then
Return fullPath
End If
Dim subPath = Path.GetDirectoryName(fullPath)
If subPath Is Nothing Then
Return Nothing
End If
Return GetExistingSubPath(subPath)
End Function
Sample usage:
Dim fullPath = "C:\testing1\testing2\testing3\testing4\testing5\TEXTBESTAND.txt"
Dim existingSubPath = GetExistingSubPath(fullPath)
Console.WriteLine(existingSubPath)

Answer 3

What I try to accomplisch is that I fist check if folder "C:" exists then "C:\testing1" then "C:\testing1\testing2" etc.
Noooooooooooo!
That's not how to do it at all! The file system is volatile: things can change between each of those checks. Moreover, file existence is only one of many things that can stop file access.
It's much better practice to try to access the file in question, and then handle the exception if it fails. Remember, because of the prior paragraph you have to be able to handle exceptions here anyway. .Exists() doesn't save you from writing that code. And each check is another round of disk access, which is about the slowest thing it's possible to do in a computer... even slower than unrolling the stack for an exception, which is the usual objection to this idea.

Answer 4

I fixed it, know I can check if multiple text files are at the locations I need, if there not I place the Textfiles at the location I need them. Then I can add something in it. (I need to put a Location of something else in it.)
Dim een As String = "C:\testing1\testing2\testing7\testing1\testing1\text.txt"
Dim twee As String = "C:\testing1\testing2\testing7\testing2\testing1\text.txt"
Dim drie As String = "C:\testing1\testing2\testing7\testing3\testing1\text.txt"
Dim vier As String = "C:\testing1\testing2\testing7\testing4\testing1\text.txt"
Dim Files As String() = {een, twee, drie, vier}
For Each route As String In Files
If System.IO.File.Exists(route) Then
MsgBox("BESTAAT HET WERKT!")
Else
Dim subroute() As String = route.Split("\"c)
Dim counting As Integer = route.Split("\"c).Length - 1
Dim tel As Integer = route.Substring(route.LastIndexOf("\") + 1).Count
Dim bestandnaam As String = route.Substring(route.LastIndexOf("\") + 1)
For count2 As Integer = 0 To route.Length - tel - 1
Dim firstbackslash As Integer = route.IndexOf("\", count2)
Dim backslash As Integer = route.IndexOf("\", count2)
Dim Mapnaam As String = route.Substring(0, backslash)
count2 = firstbackslash
If System.IO.Directory.Exists(Mapnaam) Then
Else
System.IO.Directory.CreateDirectory(Mapnaam)
End If
Next
If System.IO.File.Exists(route) Then
Else
Dim objStreamWriter As System.IO.StreamWriter
objStreamWriter = New System.IO.StreamWriter(route)
Dim label As String
Select Case route
Case een
label = "een"
Case twee
label = "twee"
Case drie
label = "drie"
Case vier
label = "vier"
End Select
Dim value As String = InputBox("Route invullen naar " & label)
'Dim objStreamWriter As New System.IO.StreamWriter(route)
objStreamWriter.Write(value)
objStreamWriter.Close()
'Using sw As System.IO.StreamWriter = System.IO.File.AppendText(route)
' sw.WriteLine(value)
'End Using
End If
End If
Next route