Question

I have a single string that contains the command-line parameters to be passed to another executable and I need to extract the string[] containing the individual parameters in the same way that C# would if the commands had been specified on the command-line. The string[] will be used when executing another assemblies entry-point via reflection.

Is there a standard function for this? Or is there a preferred method (regex?) for splitting the parameters correctly? It must handle ‘”‘ delimited strings that may contain spaces correctly, so I can’t just split on ‘ ‘.

Example string:

string parameterString = @"/src:""C:\tmp\Some Folder\Sub Folder"" /users:""[e-mail]"" tasks:""SomeTask,Some Other Task"" -someParam foo";

Example result:

string[] parameterArray = new string[] { 
  @"/src:C:\tmp\Some Folder\Sub Folder",
  @"/users:[e-mail]",
  @"tasks:SomeTask,Some Other Task",
  @"-someParam",
  @"foo"
};

I do not need a command-line parsing library, just a way to get the String[] that should be generated.

Update: I had to change the expected result to match what is actually generated by C# (removed the extra “‘s in the split strings)

Answer 1

In addition to the good and pure managed solution by Earwicker, it may be worth mentioning, for sake of completeness, that Windows also provides the CommandLineToArgvW function for breaking up a string into an array of strings:

LPWSTR *CommandLineToArgvW(
    LPCWSTR lpCmdLine, int *pNumArgs);

Parses a Unicode command line string
and returns an array of pointers to
the command line arguments, along with
a count of such arguments, in a way
that is similar to the standard C
run-time argv and argc values.

An example of calling this API from C# and unpacking the resulting string array in managed code can be found at, “Converting Command Line String to Args[] using CommandLineToArgvW() API.” Below is a slightly simpler version of the same code:

[DllImport("shell32.dll", SetLastError = true)]
static extern IntPtr CommandLineToArgvW(
    [MarshalAs(UnmanagedType.LPWStr)] string lpCmdLine, out int pNumArgs);

public static string[] CommandLineToArgs(string commandLine)
{
    int argc;
    var argv = CommandLineToArgvW(commandLine, out argc);        
    if (argv == IntPtr.Zero)
        throw new System.ComponentModel.Win32Exception();
    try
    {
        var args = new string[argc];
        for (var i = 0; i < args.Length; i++)
        {
            var p = Marshal.ReadIntPtr(argv, i * IntPtr.Size);
            args[i] = Marshal.PtrToStringUni(p);
        }

        return args;
    }
    finally
    {
        Marshal.FreeHGlobal(argv);
    }
}