a include o functie din dll facut in delphi

Salut, am o problema am deja un Dll creat in Delphi cu o functie in el,cum se poate de apelat functia in VB.NET 2010 Express
iata codul ddl din delphi

library Project2;
uses
System.SysUtils,
System.Classes;[/b]
[b]{$R *.res}
function MyNewMessage(s:string):string;
stdcall;
var i:integer;
s1:string;
begin
s1:='Hello World ';
for i:=length(s) downto 1 do
s1:=s1+s[i];
MyNewMessage:=s1;
end;
exports MyNewMessage index 1;

begin
end.

P.S.:In Delphi merge!

http://msdn.microsof...#code-snippet-2

Dar tu returnezi o adresa ce dispare imediat (s1 e alocat pe stiva) !!

Edited by neagu_laurentiu, 10 February 2014 - 20:51.

Pai si atunci cum pot so fac?

eu am incercat asa dar nu merge,poate cineva stie raspunsul?

Imports System
Imports System.Runtime.InteropServices
Module example
	<DllImport("project2.dll", CharSet:=CharSet.Unicode)> _
	Function Function MyNewMessage(ByVal hwnd As String) As String
	End Function
	Sub main()
		MyNewMessage("Hello World!")
	End Sub
End Module
Public Class Form1
	Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
		Close()
	End Sub
	Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
		MsgBox(MyNewMessage(TextBox1.Text))
	End Sub

Help me pls

Tu realizezi ca s1 dispare la iesirea din functie ? Nu are treaba cu Delphi sau .NET, e o greseala ce faci tu acolo.
Aloca dinamic pe s1 ca sa-l returnezi sau primeste ca parametru in functia aia un pointer ce-l vei "umple" sau poate are deja alocat spatiu si-l completezi etc.
Pe urma vezi cum traduci tipurile la .NET.

Quote

Pai atunci de ce in delphi merge totul super?
iata functia in delphi

function MyNewMessage(s:string):string;
stdcall;external 'c:\proj2\Project2.dll' index 1;
procedure TForm2.Button1Click(Sender: TObject);
begin
showmessage(MyNewMessage(edit1.text));
end;

Edited by simirulles, 11 February 2014 - 11:53.

Cred ca incurc eu tehnologiile, Pascal/Delphi parca are string de tip value cu o lungime de max 255 caractere, nu pointer !

Edited by neagu_laurentiu, 11 February 2014 - 12:31.

Daca vrei un dll care sa fie folosit dintr-un program creat in alt limbaj de programare, nu folosi in definita functiei de export structuri de date specifice limbajului (de ex: string). In cazul tau, foloseste pointeri catre un sir de caractere (pchar),  cu memoria initializata de functia apelanta, trimis ca si parametru.