从C＃调用Delphi函数 [英] Call Delphi Function From C#

问题描述

我有一个以下的DLL源代码。

  library Project1; 
 
使用
 System.SysUtils，
 System.Classes; 
 
 type 
 
 IStringFunctions = interface 
 ['{240B567B-E619-48E4-8CDA-F6A722F44A71}'] 
函数GetMethodValueAsString（）：PAnsiChar;标准
结束
 
 TStringFunctions = class（TInterfacedObject，IStringFunctions）
 public 
函数GetMethodValueAsString（）：PAnsiChar;标准
结束
 
 {$ R * .res} 
 
函数TStringFunctions.GetMethodValueAsString（）：PAnsiChar;标准
 begin 
结果：='test'; 
结束
 
 
程序GetImplementation（out instance：IStringFunctions）;标准出口; 
 begin 
 instance：= TStringFunctions.Create; 
结束
 
 export GetImplementation; 
 
 begin 
 end。 
  

我想在C＃中使用这样

 使用系统; 
使用System.Runtime.CompilerServices; 
使用System.Runtime.InteropServices; 
 
命名空间ConsoleApplication1 
 {
 [ComVisible（true）] 
 [ComImport，InterfaceType（ComInterfaceType.InterfaceIsIUnknown），Guid（240B567B-E619-48E4-8CDA- F6A722F44A71）
 public interface IStringFunctions 
 {
 [MethodImplAttribute（MethodImplOptions.PreserveSig）] 
 [return：MarshalAs（UnmanagedType.AnsiBStr）] 
 string GetMethodValueAsString（） ; 
} 
 
类程序
 {
 [DllImport（kernel32.dll，EntryPoint =LoadLibrary，CallingConvention = CallingConvention.StdCall）] 
 static extern int LoadLibrary（[MarshalAs（UnmanagedType.LPStr）] string lpLibFileName）; 
 
 [DllImport（kernel32.dll，EntryPoint =GetProcAddress，CallingConvention = CallingConvention.StdCall，CharSet = CharSet.Ansi）] 
 static extern IntPtr GetProcAddress（int hModule，[MarshalAs （UnmanagedType.LPStr）] string lpProcName）; 
 
 [DllImport（kernel32.dll，EntryPoint =FreeLibrary，CallingConvention = CallingConvention.StdCall）] 
 static extern bool FreeLibrary（int hModule）; 
 
 [UnmanagedFunctionPointer（CallingConvention.StdCall，CharSet = CharSet.Ansi）] 
 delegate void GetImplementation（[MarshalAs（UnmanagedType.Interface）] out IStringFunctions instance）; 
 
 static void Main（string [] args）
 {
 const string dllName =Project1.dll; 
 const string functionName =GetImplementation; 
 
 int libHandle = LoadLibrary（dllName）; 
 if（libHandle == 0）throw new异常（string.Format（无法加载库\{0} \，dllName））; 
 
 var delphiFunctionAddress = GetProcAddress（libHandle，functionName）; 
 if（delphiFunctionAddress == IntPtr.Zero）throw new Exception（string.Format（can not find function \{0} \in library \{1} \，functionName ，dllName））; 
 
 GetImplementation getImplementation =（GetImplementation）Marshal.GetDelegateForFunctionPointer（delphiFunctionAddress，typeof（GetImplementation））; 
 
 if（getImplementation！= null）
 {
 IStringFunctions instance = null; 
 getImplementation（out instance）; 
 
 if（instance！= null）
 {
 // !!!不要返回值!!! 
 String result = instance.GetMethodValueAsString（）; 
 Console.WriteLine（result）; 
} 
} 
 Console.ReadLine（）; 
} 
} 
} 
  

但是instance.GetMethodValueAsString方法没有不工作并退出代码。

我想在c＃中使用dll函数（GetMethodValueAsString）的返回值。

I不明白

我的错误在哪里？

非常感谢你

解决方案

  [return：MarshalAs（UnmanagedType.AnsiBStr）] 
  pre> 
 
 
这是错误的。您不返回在COM堆上分配的ANSI编码字符串。你正在返回一个纯C字符串，一个指向空字符的ANSI字符数组的指针。
 
 
 
你的接口声明应该是：
  [MethodImplAttribute（MethodImplOptions.PreserveSig）] 
 IntPtr GetMethodValueAsString（）; 
  
调用方法必须这样：
 
 
 IntPtr ptr = instance.GetMethodValueAsString（）; 
  string result = Marshal.PtrToStringAnsi（ptr）; 
  
当然，当您需要返回动态分配的字符串时，您的界面设计变得不切实际。你也需要出口一个发放者。处理这种情况的干净方法是使用 BSTR 。像这样：
 
 
 
  Delphi  
  IStringFunctions = interface 
 ['{240B567B-E619-48E4-8CDA-F6A722F44A71}'] 
 procedure GetMethodValueAsString（out value：WideString）;标准
结束
  
  C＃ 
  [MethodImplAttribute（MethodImplOptions.PreserveSig）] 
 void GetMethodValueAsString（[MarshalAs（UnmanagedType.BStr）] out string result）; 
  
 
I have a below DLL source code.
library Project1;

uses
  System.SysUtils,
  System.Classes;

type

  IStringFunctions = interface
    ['{240B567B-E619-48E4-8CDA-F6A722F44A71}']
    function GetMethodValueAsString():PAnsiChar; stdcall;
  end;

  TStringFunctions = class(TInterfacedObject, IStringFunctions)
  public
    function GetMethodValueAsString():PAnsiChar; stdcall;
  end;

{$R *.res}

function  TStringFunctions.GetMethodValueAsString():PAnsiChar; stdcall;
begin
  Result := 'test';
end;


procedure GetImplementation(out instance:IStringFunctions); stdcall; export;
begin
  instance := TStringFunctions.Create;
end;

exports GetImplementation;

begin
end.
I want to using in C# like this
using System;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;

namespace ConsoleApplication1
{
    [ComVisible(true)]
    [ComImport, InterfaceType(ComInterfaceType.InterfaceIsIUnknown), Guid("240B567B-E619-48E4-8CDA-F6A722F44A71")]
    public interface IStringFunctions
    {
        [MethodImplAttribute(MethodImplOptions.PreserveSig)]
        [return: MarshalAs(UnmanagedType.AnsiBStr)]
        string GetMethodValueAsString();
    }

    class Program
    {
        [DllImport("kernel32.dll", EntryPoint = "LoadLibrary", CallingConvention = CallingConvention.StdCall)]
        static extern int LoadLibrary([MarshalAs(UnmanagedType.LPStr)] string lpLibFileName);

        [DllImport("kernel32.dll", EntryPoint = "GetProcAddress", CallingConvention = CallingConvention.StdCall, CharSet = CharSet.Ansi)]
        static extern IntPtr GetProcAddress(int hModule, [MarshalAs(UnmanagedType.LPStr)] string lpProcName);

        [DllImport("kernel32.dll", EntryPoint = "FreeLibrary", CallingConvention = CallingConvention.StdCall)]
        static extern bool FreeLibrary(int hModule);

        [UnmanagedFunctionPointer(CallingConvention.StdCall, CharSet = CharSet.Ansi)]
        delegate void GetImplementation([MarshalAs(UnmanagedType.Interface)] out IStringFunctions instance);

        static void Main(string[] args)
        {
            const string dllName = "Project1.dll";
            const string functionName = "GetImplementation";

            int libHandle = LoadLibrary(dllName);
            if (libHandle == 0) throw new Exception(string.Format("Could not load library \"{0}\"", dllName));

            var delphiFunctionAddress = GetProcAddress(libHandle, functionName);
            if (delphiFunctionAddress == IntPtr.Zero) throw new Exception(string.Format("Can't find function \"{0}\" in library \"{1}\"", functionName, dllName));

            GetImplementation getImplementation = (GetImplementation)Marshal.GetDelegateForFunctionPointer(delphiFunctionAddress, typeof(GetImplementation));

            if (getImplementation != null)
            {
                IStringFunctions instance = null;
                getImplementation(out instance);

                if (instance != null)
                {
                    //!!! don't return value !!!!
                    String result = instance.GetMethodValueAsString();
                    Console.WriteLine(result);
                }
            }
            Console.ReadLine();
        }
    }
}
But instance.GetMethodValueAsString method doesn't working. And exit code.

I want to use returning value from dll function(GetMethodValueAsString) in c#.

I don't understand.

Where's my fault?

Thank you so much
解决方案
[return: MarshalAs(UnmanagedType.AnsiBStr)]
This is wrong. You are not returning an ANSI encoded string, allocated on the COM heap. You are returning a plain C string, a pointer to null-terminated array of ANSI characters.

Your interface declaration should be:
[MethodImplAttribute(MethodImplOptions.PreserveSig)]
IntPtr GetMethodValueAsString();
Calling the method must be done like this:
IntPtr ptr = instance.GetMethodValueAsString();
string result = Marshal.PtrToStringAnsi(ptr);
Of course, your interface design becomes rather impractical when you need to return a dynamically allocated string. You'd need to export a deallocator too. The clean way to deal with this is to use a BSTR. Like this:

Delphi
IStringFunctions = interface
  ['{240B567B-E619-48E4-8CDA-F6A722F44A71}']
  procedure GetMethodValueAsString(out value: WideString); stdcall;
end;
C#
[MethodImplAttribute(MethodImplOptions.PreserveSig)]
void GetMethodValueAsString([MarshalAs(UnmanagedType.BStr)] out string result);


                        
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