Dim strAppDir As String = Path.GetDirectoryName( _
    Assembly.GetExecutingAssembly().GetName().CodeBase)
Dim strFullPathToMyFile As String = Path.Combine(strAppDir, "myFileName.txt")

MessageBox.Show(String.Format("Path to the application is: '{0}'." + _
    "Full path to the file in the application folder is: '{1}'", _
    strAppDir, strFullPathToMyFile))

        String strAppDir = Path.GetDirectoryName(
            Assembly.GetExecutingAssembly().GetName().CodeBase);
        String strFullPathToMyFile = Path.Combine(strAppDir, "fileName.txt");

        MessageBox.Show(String.Format("Path to the application is: '{0}'." +
            "Full path to the file in the application folder is: '{1}'",
            strAppDir, strFullPathToMyFile));