I am pretty new to Delphi. We tried to import a C++ or C# dll to Delphi. Our requirement is to import the library as COM object. Since there are multiple classes and structs we have in the DLL , we don’t want it to P/Invoke the methods. We tried to build a DLL in C++/C# and as MFC ActiveX(ocx component). I have been following these links to create a DLL :
- http://www.codeproject.com/Articles/505791/Writing-Simple-COM-ATL-DLL-for-VS
- https://www.simple-talk.com/dotnet/visual-studio/build-and-deploy-a-net-com-assembly/
- https://john.nachtimwald.com/2012/04/08/wrapping-a-c-library-in-comactivex/
and this link(http://wiki.freepascal.org/LazActiveX) to import the TLIB I created. All the DLLs I create comes to stopping point where I create an object in Delphi.
The one I created in C# is :
using System;
using System.Runtime.InteropServices;
using System.IO;
using System.Text;
using System.Threading.Tasks;
namespace CSharpSampleLib
{
[ComVisible(true),
Guid("CDBFD892-7473-4AC4-8B44-D75A828599AD")]
[InterfaceType(ComInterfaceType.InterfaceIsDual)]
public interface ICSharpCom
{
[DispId(1)]
void Init();
[DispId(2)]
int AddNumbers(int num1, int num2);
[DispId(3)]
String StringConcat(String num1, String num2);
}
[Guid("D51F086B-B593-436D-8900-92CDC1E427CE"),
InterfaceType(ComInterfaceType.InterfaceIsIDispatch)]
public interface CSharpCom_Events
{
}
[Guid("4AB74C5C-6F3C-4B15-9E00-5174551B50A2"),
ClassInterface(ClassInterfaceType.None)]
[ProgId("Sample.CSharpCom")]
[ComVisible(true)]
public class CSharpCom : ICSharpCom
{
public CSharpCom() { }
public void Init() { }
public int AddNumbers(int num1, int num2)
{
return num1 + num2;
}
public String StringConcat(String str1, String str2)
{
return str1 + str2;
}
}
}
We tried two options to invoke the Type library we imported.
program CSharpDemo;
uses comobj, CSharpSampleLib_1_0_TLB;
var
objCsLib1:ICSharpCom;
objCsLib2:OLEVariant;
begin
objCsLib1:=CoCSharpCom.Create; // Method 1
objCsLib2:= CreateOleObject('CSharpSampleLib.CSharpCom'); //Method 2
end.
Method 1 gives:
Method 2 gives:
We made sure that the library is registered and found the GUID in Wow6432Node>CLSID>
I hope this is the correct way to create an object. May I know what I am missing in here?
