I use Unmanaged Exports to create a native .dll from .NET .dll so I can access .NET code from Delphi without COM registration.
For example I have this .NET assembly:
using System;
using System.Collections.Generic;
using System.Text;
using RGiesecke.DllExport;
using System.Runtime.InteropServices;
namespace DelphiNET
{
[ComVisible(true)]
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
[Guid("ACEEED92-1A35-43fd-8FD8-9BA0F2D7AC31")]
public interface IDotNetAdder
{
int Add3(int left);
}
[ComVisible(true)]
[ClassInterface(ClassInterfaceType.None)]
public class DotNetAdder : DelphiNET.IDotNetAdder
{
public int Add3(int left)
{
return left + 3;
}
}
internal static class UnmanagedExports
{
[DllExport("createdotnetadder", CallingConvention = System.Runtime.InteropServices.CallingConvention.StdCall)]
static void CreateDotNetAdderInstance([MarshalAs(UnmanagedType.Interface)]out IDotNetAdder instance)
{
instance = new DotNetAdder();
}
}
}
When I define the same interface in Delphi, I can easily use the .NET object:
type
IDotNetAdder = interface
['{ACEEED92-1A35-43fd-8FD8-9BA0F2D7AC31}']
function Add3(left : Integer) : Integer; safecall;
end;
procedure CreateDotNetAdder(out instance : IDotNetAdder); stdcall;
external 'DelphiNET' name 'createdotnetadder';
var
adder : IDotNetAdder;
begin
try
CreateDotNetAdder(adder);
Writeln('4 + 3 = ', adder.Add3(4));
except
on E: Exception do
Writeln(E.ClassName, ': ', E.Message);
end;
end.
See my Delphi question and answers for details.
My question:
Is something like this possible in FoxPro? I've tried the following which fails with Data type mismatch error on line createdotnetadder(@ldnw):
DECLARE createdotnetadder IN DelphiNET.dll object @ ldnw
ldnw = 0
createdotnetadder(@ldnw)
loObject = SYS(3096, ldnw)
? loObject.Add3(4)
Can I define interface in FoxPro similarly how I did it in Delphi? If not, can I use this .dll from FoxPro at all? I use Visual FoxPro 9.0 SP2. Thanks.