Arguments with spaces

Question

I would like to pass some arguments to a little program i wrote. Its a program that expects 2 arguments. When i call it like this:

d:\littleProgram.exe d:\test\folder\ test.pdf

It works fine.

But when i try this:

d:\littleProgram.exe d:\test 2\folder\ test.pdf

It thinks is gets 3 arguments...

I tried quotes like this:

d:\littleProgram.exe "d:\test 2\folder\" test.pdf

No luck.

This is the vb code:

Module Module1
        Sub Main(ByVal sArgs() As String)
            If sArgs.Length = 0 Then
                ... some code
            ElseIf sArgs.Length = 2 Then
                ... some code
            End If
         End Sub
End Module

Answer 1

The problem was that when i use quotes arround first argument, i was actually escaping the closing qoute:

d:\littleProgram.exe "d:\test 2\folder\" test.pdf

This works fine now:

d:\littleProgram.exe "d:\test 2\folder" test.pdf

In combination with putting the \ inside the code of the program

Answer 2

Command Line Arguments are Space Delimited.

If you need to pass an argument such as a filename that has (or may have) spaces you can enclose it in double quotes.

The exception to this is when arguments end with \ in which case you have to escape this with another \

So in your case this is what you need:

d:\littleProgram.exe "d:\test 2\folder\\" "test.pdf"

So your code would look like this:

For i As Integer = 0 To My.Application.CommandLineArgs.Count - 1
    Debug.Writeline(My.Application.CommandLineArgs(i))
Next

Output:

d:\test 2\folder\
test.pdf

A simpler approach might be to remove the trailing slash and add the directory and filename together using Path.Combine or just pass the fully qualified name as the argument (enclosed in double quotes)

Answer 3

The argument parsing har some strange rules for escaping characters, it's the \" character combination in the arguments that causes the problem. This is a problem with the CommandLineToArgvW method in Windows. See for example the article Commandline args ending in \" are subject to CommandLineToArgvW whackiness

Get the unparsed command line and parse it to get the parameters as expected:

Dim arguments As String() = _
  Regex.Matches(Environment.CommandLine, "(?:""[^""]*""|[^ ]+)") _
  .Cast(Of Match)().Select(Function(m) m.Value).Skip(1).ToArray()

Note: This parsing doesn't handle escape sequences as the original method, so you can't use for example "" or \" inside a quoted parameter to put a quotation mark in it. If you want to use the original method, you need to follow it's escaping rules and the arguments would have to be written as:

d:\littleProgram.exe "d:\test 2\folder\\" test.pdf