Using C# DLL in Lazarus
lazarus / 67-Windows

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JohnRambo · 2017-09-20 18:16

At first I admit that in C # I am green like chives. I want to prepare
a C# DLL using the UnmanagedExports tool
(https://www.nuget.org/packages/UnmanagedExports) in the C # DLL.
Here's an example by
author:https://stackoverflow.com/a/2055508/1919267 .
So far ok, managed to produce a DLL and use it in Delphi. But there is
a problem: when I want to use the same file in Lazarus, it returns
nothing. The code:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i var  adder
: IDotNetAdder;begin  try   CreateDotNetAdder(adder);   Writeln('4 + 3
= ', adder.Add3(4));  returns me 0 (so I am thinking that DLL
response  is nil). Is there any solution to fix that? Should I need to
fix my pascal code or fix that DLL?

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avra · 2017-09-21 09:11

Next time you cross post I will hold my comments... 
Please do not cross post in the future.

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tudi_x · 2017-09-21 09:30

@avra - the deletion of posts does not seem to work. maybe he opened a
new one due to code not inserted as recommended in the first place.

@rambo - i think you need to have a handler for the dll and define the
external function, something like
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
TGetDeviceInfo = function(AIndex: integer): PTDeviceInfoRecord; cdecl;
after you define the handler and the function you can use it.

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JohnRambo · 2017-09-21 13:30

Sorry for double topic but I can't delete topic in wrong category. I
cant use COM, because I need to use old version of Lazarus (without
ActiveX).
In my code I declare procedure in static way:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i var  Form1:
TForm1;  procedure createdotnetadder(out instance:IDotNetAdder);
stdcall external 'DelphiNETstd.dll' name
'createdotnetadder';implementation{ TForm1 }When I try to do it
dynammicaly nothing work, only more problems. I don't understand that
Delphi do it perfectly, but Lazarus not. In attachments I put .dll
file and my pas unit. I don't asking about do it for me but to show me
the way

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JohnRambo · 2017-09-21 14:53

OK I made it.
Firstly we need to get some information:
https://stackoverflow.com/a/9353800
"In C#/C++ you will need to define the Result as out Parameter, in
order to maintain binary code compatibility of stdcall calling
conventions" - thats the key. In my C# code I was use return. For
Delphi its ok, but for Lazarus it is problematic. So I retyped my c#
code from:
Code: C#  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i  
 [ComVisible(true)]    [ClassInterface(ClassInterfaceType.None)]   
public class DotNetAdder : DelphiNET.IDotNetAdder    {        public
void Add3(int left)        {            return= left + 3;            
      }    }
to Code: C#  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i  
 [ComVisible(true)]    [ClassInterface(ClassInterfaceType.None)]   
public class DotNetAdder : DelphiNET.IDotNetAdder    {        public
void Add3(int left,out int result)        {            result= left +
3;                    }    }And change my pascal code from:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
//interface:  type  IDotNetAdder = interface 
['{ACEEED92-1A35-43fd-8FD8-9BA0F2D7AC31}']    function Add3(left :
integer):integer; stdcall;  end; //execution:var  adder :
IDotNetAdder;begin  try   CreateDotNetAdder(adder);   Writeln('4 + 3 =
', adder.Add3(4));
to
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
 //interface:  type  IDotNetAdder = interface 
['{ACEEED92-1A35-43fd-8FD8-9BA0F2D7AC31}']    function Add3(left :
integer;out result:integer); stdcall;  end;
 //execution: CreateDotNetAdder(adder);   i:=4;   finally 
 adder.Add3(i,x);  showmessage('4 + 3 = '+ (inttostr(x)));

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Cyrax · 2017-09-21 15:01

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i void
Add3(int left)
translates to

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
Add3(left:integer)
If you want result from your subroutine, you need to change C# code to

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i int
Add3(int left)
and Pascal version to

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i function
Add3(left:integer) : integer