Thread: C# and DLL passing and retrieving data

  1. #1
    Registered User
    Join Date
    Nov 2009
    Posts
    53

    C# and DLL passing and retrieving data

    Hello,

    I have a C# program going and want to be able to call the DLL and receive back the data requested through a pointer.

    Below is the DLL import within my C# code.
    Code:
    [DllImport("MyTest.dll")]
            public static extern int ReadNetwork(Byte[] ROM_ID);
    Below is the code in the DLL
    Code:
    int _stdcall ReadNetwork(unsigned char* Array1)
    {
    	ReadDevice(readBackArray);
    	for(i = 0; i < 20; i++)
    	{
    		Array1[i] = readBackArray[i];
    	}
    
    	return 1;
    }
    And below how I'mm calling the DLL and trying to print out the results.

    Code:
    int errorCheck;
    byte[] testArray;
    testArray = new byte[12];
    string value;
    
    errorCheck = ReadNetwork(testArray);
    MessageBox.Show("Return Value: " + errorCheck.ToString());
    value = ASCIIEncoding.ASCII.GetString(testArray);
    MessageBox.Show("Array String: " + value);
    I've tried changing the return values in the DLL's ReadNetwork() function and that works ok, so I know I'm calling the DLL and it runs ok, but printing the result back is where I'm having the problem. Any help will be appreciated.

  2. #2
    Registered User
    Join Date
    Oct 2006
    Posts
    3,420
    how does the ReadNetwork function in the DLL know how big the array is?
    What can this strange device be?
    When I touch it, it gives forth a sound
    It's got wires that vibrate and give music
    What can this thing be that I found?

  3. #3
    Hurry Slowly vart's Avatar
    Join Date
    Oct 2006
    Location
    Rishon LeZion, Israel
    Posts
    6,794
    why are you allocating 12 bytes when function fills 20?

    See samples using StringBuilder
    C# and the char* mess
    All problems in computer science can be solved by another level of indirection,
    except for the problem of too many layers of indirection.
    David J. Wheeler

Popular pages Recent additions subscribe to a feed

Similar Threads

  1. retrieving data from a mysql table thorugh c++
    By daehan00 in forum C++ Programming
    Replies: 1
    Last Post: 10-09-2012, 11:37 AM
  2. Retrieving data from a file
    By kamitsuna in forum C++ Programming
    Replies: 45
    Last Post: 02-27-2010, 09:37 PM
  3. Retrieving Data from DLL
    By JJFMJR in forum C++ Programming
    Replies: 11
    Last Post: 08-18-2008, 07:44 AM
  4. Retrieving Browser Data
    By Siphon in forum C++ Programming
    Replies: 2
    Last Post: 04-07-2008, 07:31 AM
  5. retrieving data from listboxes
    By luddeb in forum Windows Programming
    Replies: 6
    Last Post: 01-10-2006, 04:08 AM