Use importTextData / Want to open to a file directory only / Then user picks file

I have a trusted function to import a text file from a button.   It works fine when I specify the file path including a specific text file.  I am wanting to open to the file directory and let the user select from the .txt files in that folder.  If I don't include an actual file.txt name, nothing happens, the path to the directory with the text files does not open.  The code I'm trying to use with the button is:

var thepath = getCurrentDirectory;

myImportTextData(thepath);

My trusted function code is:

myImportTextData = app.trustedFunction(function(cPath)
{
app.beginPriv();
this.importTextData(cPath);
app.endPriv();
});