Delphi写的DLL回调C#

C#的调用Delphi的DLL没有问题，DLL回调时遇到了麻烦，网上找了个方法，解决了这个问题

Delphi部分，列举了三种回调函数定义

[delphi]view plaincopy

1. library test;
2. uses
3. SysUtils;
4. {$R *.res}
5. type
6. TCallback = procedure (P: PChar); stdcall;
7. TMethodCallback = procedure (P: PChar) of object; stdcall;
8. procedure DllTest1(Callback: TCallback; P: PChar; I: Integer); stdcall;
9. var
10. S: string;
11. begin
12. S := Format('DllTest1 ''%s'' %d', [P, I]);
13. if Assigned(Callback) then
14. Callback(PChar(S));
15. end;
16. procedure DllTest2(_Callback: Pointer; P: PChar; I: Integer); stdcall;
17. var
18. Callback: TMethodCallback absolute _Callback;
19. S: string;
20. begin
21. S := Format('DllTest2 ''%s'' %d', [P, I]);
22. if Assigned(Callback) then
23. Callback(PChar(S));
24. end;
25. procedure DllTest3(Callback: TMethodCallback; P: PChar; I: Integer); stdcall;
26. var
27. S: string;
28. begin
29. S := Format('DllTest3 ''%s'' %d', [P, I]);
30. if Assigned(Callback) then
31. Callback(PChar(S));
32. end;
33. exports
34. DllTest1,
35. DllTest2,
36. DllTest3;
37. begin
38. end.

C#部分

[csharp]view plaincopy

1. using System;
2. using System.Collections.Generic;
3. using System.Text;
4. using System.Runtime.InteropServices;
5. namespace DllTest
6. {
7. class Program
8. {
9. public struct Method
10. {
11. public IntPtr code;
12. public IntPtr data;
13. }
14. [DllImport("Test.dll", CallingConvention = CallingConvention.StdCall, CharSet = CharSet.Ansi, EntryPoint = "DllTest1")]
15. public static extern void DllTest1(IntPtr p, [MarshalAs(UnmanagedType.LPStr)] string s, int i);
16. [DllImport("Test.dll", CallingConvention = CallingConvention.StdCall, CharSet = CharSet.Ansi, EntryPoint = "DllTest2")]
17. public static extern void DllTest2(IntPtr p, [MarshalAs(UnmanagedType.LPStr)] string s, int i);
18. [DllImport("Test.dll", CallingConvention = CallingConvention.StdCall, CharSet = CharSet.Ansi, EntryPoint = "DllTest3")]
19. public static extern void DllTest3(Method m, [MarshalAs(UnmanagedType.LPStr)] string s, int i);
20. public delegate void Callback([MarshalAs(UnmanagedType.LPStr)] string s);
21. public delegate void MethodCallback(IntPtr self, [MarshalAs(UnmanagedType.LPStr)] string s);
22. public static void ShowInfo(string s)
23. {
24. Console.WriteLine("Info: " + s);
25. }
26. public static void ShowMethodInfo(IntPtr self, string s)
27. {
28. Console.WriteLine("Info: " + s);
29. }
30. static void Main(string[] args)
31. {
32. Method m;
33. Callback info = ShowInfo;
34. MethodCallback methodInfo = ShowMethodInfo;
35. IntPtr p = Marshal.GetFunctionPointerForDelegate(info);
36. IntPtr pm = Marshal.GetFunctionPointerForDelegate(methodInfo);
37. // function callback example
38. DllTest1(p, "test", 42);
39. // method callback example 1
40. DllTest2(pm, "test", 42);
41. // method callback example 2
42. m.code = pm;
43. m.data = IntPtr.Zero;
44. DllTest3(m, "test", 42);
45. }
46. }
47. }