VB.net console app calling a Delphi (win32 DLL)

[SpeedBWild]

I have been giving the task of taking a Delphi console application and making it into a Win32 DLL. From there I then need to be able to call the functions of the DLL from a VB.NET console application (during the testing stage).

I have several functions in my Delphi (Win32 DLL) and I can call all of them from the VB.NET console application. The one problem I am running into is for one of the functions I need to pass in a value and then based on that value run the function. This is not working. If I hard code in a value everything works, if I try to pass it in it fails. Below is the code I am using trying to pass in a value and use (sX)

Delphi code:
function GetData(sX :string; var sY :string) :integer;
begin
sY := GetData2('','','',sX,'');
result := 0;
end;

VB.net code:
<DllImport("C:\TestDLL.dll", EntryPoint:="GetData", SetLastError:=False, CharSet:=CharSet.Ansi, _
ExactSpelling:=True, CallingConvention:=CallingConvention.StdCall)> _
Private Function GetData(ByVal pX As IntPtr, ByRef pY As IntPtr) As Int32
End Function



Dim MAXLen as int32 =255
Dim sXVal As String = "sssssss".PadRight(MAXLen , Chr(0))
Dim sYVal As String = "".PadRight(MAXLen , Chr(0))
Dim ptXVal As IntPtr = Marshal.StringToHGlobalAnsi(sXVal)
Dim ptYVal As IntPtr = Marshal.StringToHGlobalAnsi(sYVal)
Dim i As Int32 = -1
Try
i = GetData(ptXVal , ptYVal )
Catch e As System.Runtime.InteropServices.SEHException
Console.WriteLine(e.ErrorCode())
Console.WriteLine(e.Message)
Console.WriteLine(e.Source)
Catch e As Exception
Console.WriteLine(e.Message)
Finally
sYVal = Marshal.PtrToStringAnsi(ptYVal )
Marshal.FreeHGlobal(ptXVal)
Console.WriteLine(sYVal)
End Try

I am getting the System.Runtime.InteropServices.SEHException
exception. External component has thrown an exception.

Any ideas? If I am posting to the wrong forum, I apologize in advance. I'm not really sure where to post to.

Thanks,


Thanks

 

[butthead]

Dim ptXVal As IntPtr = Marshal.StringToHGlobalAnsi(sXVal)
GetData(sX :string; var sY :string) :integer;

are you sure "sx" and "ptxVal" are the same type.

what is As IntPtr

I assume "sX :string;" is one argument.

excuse my intrusion, I am just excercising my
frontal lobe.

tomcruz.net

 

[SpeedBWild]

sX and ptXval are not of the same type. IntPTr is a integer pointer in VB.net.

In my VB.net code I need to marshal my string to a pointer.

In my Delphi DLL, (here the problem) I don't know how to read the value of the pointer I pass in.

Any ideas?

 

[butthead]

dont see how you are going to get any results untill
sX and ptXval are the same type.


tomcruz.net