Saving files

[Simon Stochholm]

How can I save a file to the EV3 while my program is running?

[Tcm0]

Why do you want to do that?

[Helmut Wunder]

JFYI, to me it’s also important to create files by a running program, e.g., to store settings a/o data which can be reloaded and rewritten/updated .
Examples:
sound (rhythm) patterns for spoken words,
x,y,z coordinates for teached-in robot arm positions,
look-up tables of different kind,
log files of different kind,
recognized patterns by a neural net,
2D environment maps of rooms and mazes….

[Tcm0]

Okay, I thought that you wanted to upload a program during running another program.
You can test the “general” file access options of visual studio. They might work.

[Simon Stochholm]

I need it for saving settings, so that I can read those settings if the ev3 has been turned off. I have tried the following ways:
1) private static string path = Path.GetDirectoryName(Assembly.GetAssembly(typeof(AbstractMemory)).CodeBase);
2) static string filePath = “/home/root/apps/test.dat”;
3) static DirectoryInfo di = new DirectoryInfo(Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location));
4)private static string filePath = “test.dat”;
5)private static string filePath = Path.Combine(Environment.CurrentDirectory, “test.dat”);
But none of them seems to work for me.

Can anyone give a good example of saving to a file on the ev3, or just the correct way to find the correct path to save the file

[Simon Stochholm]

[SOLVED]
It turned out that I had forgotten to serialize part of my classes.
In order to save files use this path:
private static string filePath = Path.Combine(Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location), “test.dat”);

And then just read and write bytes to and from this filePath

[Helmut Wunder]

how is it possible to read/write variables other than bytes dircty,
without having to rearrange and convert data from basic bytes, e.g.
int16,
int32,
float64,
strings
arrays of single data type (e.g., arrays[6] of float)
structures

like fprintf, fscanf, and fputs etc. in C:

   FILE * pFile;
   int n;
   char name [100];

   pFile = fopen ("myfile.txt","w");
   for (n=0 ; n<3 ; n++)
   {
     puts ("please, enter a name: ");
     gets (name);
     fprintf (pFile, "Name %d [%-10.10s]\n",n,name);
   }
   fclose (pFile);

//...
  pFile = fopen ("myfile.txt","w+");
  fprintf (pFile, "%f %s", 3.1416, "PI");
  rewind (pFile);
  fscanf (pFile, "%f", &f);
  fscanf (pFile, "%s", str);
  fclose (pFile);
  printf ("I have read: %f and %s \n",f,str); 

[Simon Stochholm]

What I have done is simply to serialize and deserialize an object, and then just return whatever object I need: (I had to do it this way, because the file was generated on the fly)
private static string filePath = Path.Combine(Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location), “test.dat”);

public static void Serialize(IDictionary<string, Action> combos)
{
var formatter = new BinaryFormatter();
var stream = new MemoryStream();

formatter.Serialize(stream, combos);
stream.Position = 0;
var bytes = stream.GetBuffer();

using (var streamer = File.Create(filePath))
{
streamer.Write(bytes, 0, bytes.Length);
}
}

public static IDictionary<string, Action> Deserialize()
{
var bytes = File.ReadAllBytes(filePath);
var formatter = new BinaryFormatter();
var stream = new MemoryStream(bytes);
var action = (IDictionary<string, Action>)formatter.Deserialize(stream);
return action;
}

If the file already exists on the EV3 you can simply do like this:
string text = System.IO.File.ReadAllText(filePath);

// Display the file contents to the console. Variable text is a string.
LcdConsole.WriteLine(“Contents of WriteText.txt = {0}”, text);

// Example #2
// Read each line of the file into a string array. Each element
// of the array is one line of the file.
string[] lines = System.IO.File.ReadAllLines(filePath);

// Display the file contents by using a foreach loop.
LcdConsole.WriteLine(“Contents of WriteLines2.txt = “);
foreach (string line in lines)
{
// Use a tab to indent each line of the file.
LcdConsole.WriteLine(“\t” + line);
}

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