Oxygen Basic

Programming => Example Code => General => Topic started by: chrisc on April 13, 2018, 03:48:24 PM

Title: C# program calling O2 dll and pass parameters to each other
Post by: chrisc on April 13, 2018, 03:48:24 PM

I have atteched 3 programs where a C# program calls  2  O2 dlls
which can pass parameters to each other and back.

C# program  GitO2data.exe

Code: [Select]

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

// need this to run DllImport
using System.Runtime.InteropServices;

namespace GitO2Data
{
    public partial class Form1 : Form
    {
        //  Note that this program is compiled to 64 bits while its O2 dlls are also compiled to 64 bits
        //  setup the DLLs

         [DllImport("DllMain.DLL", EntryPoint = "RetString")]
          [return: MarshalAs(UnmanagedType.AnsiBStr)]
          public static extern string RetString([MarshalAs(UnmanagedType.AnsiBStr)]
             ref string Seltxt);

        // reference  https://stackoverflow.com/questions/16332701/how-to-call-c-dll-in-c-sharp

        [DllImport("Greet.dll", EntryPoint = "greet")]
        public static extern int greet(string rfst);

        public Form1()
        {
            InitializeComponent();
        }

        // Button to get Message from an  O2 DLL
        private void button1_Click(object sender, EventArgs e)
        {
             // display the greeting
            string txtmynam = "Good Man";
            int dummynum = greet(txtmynam);

            MessageBox.Show(" number from O2  : " + dummynum.ToString() );
         }


        // Button to get a string from an  O2 DLL
        private void button2_Click(object sender, EventArgs e)
        {
            string txtReturn = "";
            // Obtain the entered text
               string EnterText = textBox1.Text.Trim();

            // get the return string
               txtReturn = RetString(ref EnterText);

            // Display the return string on the screen
             MessageBox.Show(" String  from O2  dll : " + txtReturn);
        }
    }
}


and the Dllmain.o2bas    (thanxx to Charles )

Code: [Select]


% dll
% filename "DllMain.dll"
uses rtl64

 def TRIM ltrim(rtrim(%1))

function RetString(stwant as string) as string, export
If LCASE(TRIM(stwant)) = "one" then
   return  "First string (one)  was entered"
else
   return  " Other string was entered"
end if
end function


the Greet.o2bas   (thanxx to Charles )

Code: [Select]

% dll
% filename "Greet.dll"
uses rtl64

function greet(stgreet as char) as long, export

print "hello "+stgreet

return   1
end function


Title: Re: C# program calling O2 dll and pass parameters to each other
Post by: chrisc on April 13, 2018, 03:49:37 PM

Note that all progs are compiled to 64bits

Title: Re: C# program calling O2 dll and pass parameters to each other
Post by: Charles Pegge on April 13, 2018, 09:13:32 PM

Thanks Chris,

This C# stuff looks really intimidating.

I presume Visual Studio churns out most of the code.

Title: Re: C# program calling O2 dll and pass parameters to each other
Post by: chrisc on April 13, 2018, 09:37:12 PM

Not really Charles,  the Visual designer IDE only helps out with the visual form creation and where to locate controls
like the buttons and txt boxes.  i still need to type in the main codes  which is helped by  IDE's intelligent sense.
i would say it is 30% work by the IDE and 70% by the programmer.  but the plus side of the IDE is the debugging that is
quite efficient.

C# is not very secure as it uses MSIL or clear text pcode  and is easier to hack.   that's why we need O2 which
compiles to native codes.     using O2 dll is important as the main C# calling program is easily hackable but the O2 dlls are
tough to hack.  thus we place all the important functions into O2 dlls 

your o2 compiler is very good as shown above we can now interface with c#, thanxx a lot Charles