本文介绍了从C＃.NET应用程序调用Delphi DLL的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
编辑：我已经发布了一个更好的实现，在下面。我在这里离开这里，所以答案是有道理的。
我在Delphi中编写了一个DLL的正确方法，从C＃调用它，传递和返回字符串。很多信息不完整或不正确。经过多次尝试和错误，我找到了解决方案。
这是使用Delphi 2007和VS 2010编译的。我怀疑它可以在其他版本中正常工作。 p>
这是Delphi代码。请记住在项目中包含版本信息。
库DelphiLibrary;
使用SysUtils;
//使用Delphi 2007编译
//注意：如果您的项目没有包含版本信息，您可能会
//收到错误在编译C＃应用程序时，ResolveManifestFiles任务意外失败
//。
{$ R * .res}
//示例函数接受一个输入整数和输入字符串，并返回
// inputInt + 1和inputString + ''+ IntToStr（outputInt）作为输出
//参数。如果成功，返回结果为nil（null），否则为
//异常消息字符串。
//注意：我在下面发布了一个更好的版本。你应该使用它。
函数DelphiFunction（inputInt：integer; inputString：PAnsiChar;
out outputInt：integer; out outputString：PAnsiChar）
：PAnsiChar;标准出口;
var s：string;
begin
outputInt：= 0;
outputString：= nil;
try
outputInt：= inputInt + 1;
s：= inputString +''+ IntToStr（outputInt）;
outputString：= PAnsiChar（s）;
结果：= nil;
除了
对e：exception do结果：= PAnsiChar（e.Message）;
结束
结束
//我会以为在函数声明结尾处有export
//（上面）已经足够导出函数，但是我无法得到它
//在没有这行的情况下工作。
导出DelphiFunction;
begin
end。
这是C＃代码：
使用系统;
使用System.Runtime.InteropServices;
命名空间CsharpApp
{
类程序
{
//我将DelphiLibrary.dll添加到我的项目中（不是参考文献，而是
//添加现有文件）。在dll的属性中，我将BuildAction
//设置为None，将Copy to Output Directory复制到Always always。
//确保您的Delphi DLL包含版本信息。
[DllImport（DelphiLibrary.dll，
CallingConvention = CallingConvention.StdCall，
CharSet = CharSet.Ansi）]
public static extern
string DelphiFunction（int inputInt，string inputString，
out int outputInt，out string outputString）;
static void Main（string [] args）
{
int inputInt = 1;
string inputString =这是一个测试;
int outputInt;
string outputString;
//注意：我在下面发布了一个更好的版本。你应该使用它。
Console.WriteLine（inputInt = {0}，intputString = \{1} \，
inputInt，inputString）;
var errorString = DelphiFunction（inputInt，inputString，
out outputInt，out outputString）;
if（errorString！= null）
Console.WriteLine（Error = \{0} \，errorString）;
else
Console.WriteLine（outputInt = {0}，outputString = \{1} \，
outputInt，outputString）;
Console.Write（按回车：）;
Console.ReadLine（）;
}
}
}
我希望这些信息有助于某人否则不必像我一样拉头发。
解决方案
根据对我的帖子的回复，我创建了一个新的示例，它为返回的字符串使用字符串缓冲区，而不是返回PAnsiChars。
Delphi DLL源代码：
库DelphiLibrary;
使用SysUtils;
//使用Delphi 2007编译
//注意：如果您的项目没有包含版本信息，您可能会
//收到错误在编译C＃应用程序时，ResolveManifestFiles任务意外失败
//。
{$ R * .res}
//保留字符串的注释。我原来写这个，所以
//输出字符串只是一个PAnsiChar。但是有几个人指出，
//因为Delphi字符串是引用计数的，这是一个坏主意，因为
//字符串的内存在使用之前可能会被覆盖。
//
//因此，我重写了该示例，以便您必须传递
//结果字符串的缓冲区。我看到一些如何做到这一点的例子，他们在哪里
//也返回了实际的字符串长度。这不是必需的，因为
// string是空值终止的，实际上这些示例本身从未使用
//返回的字符串长度。
//示例函数接受一个输入整数和输入字符串，并返回
// inputInt + 1和inputString ++ IntToStr（outputInt）。如果成功，
//返回结果为true，否则errorMsgBuffer包含
//异常消息字符串。
函数DelphiFunction（inputInt：integer;
inputString：PAnsiChar;
输出Int：integer;
outputStringBufferSize：integer;
var outputStuffBuffer：PAnsiChar;
errorMsgBufferSize ：integer;
var errorMsgBuffer：PAnsiChar）
：WordBool;标准出口;
var s：string;
begin
outputInt：= 0;
try
outputInt：= inputInt + 1;
s：= inputString +''+ IntToStr（outputInt）;
StrLCopy（outputStringBuffer，PAnsiChar（s），outputStringBufferSize-1）;
errorMsgBuffer [0]：=＃0;
结果：= true;
除了
对于e：exception do
begin
StrLCopy（errorMsgBuffer，PAnsiChar（e.Message），errorMsgBufferSize-1）;
结果：= false;
结束
结束
结束
//我会以为在函数声明结尾处有export
//（上面）已经足够导出函数，但是我无法得到它
//在没有这行的情况下工作。
导出DelphiFunction;
begin
end。
C＃代码：
使用系统;
使用System.Runtime.InteropServices;
命名空间CsharpApp
{
类程序
{
//我将DelphiLibrary.dll添加到我的项目中（不是参考文献，而是
//添加现有文件）。在dll的属性中，我将BuildAction
//设置为None，将Copy to Output Directory复制到Always always。
//确保您的Delphi DLL包含版本信息。
[DllImport（DelphiLibrary.dll，
CallingConvention = CallingConvention.StdCall，
CharSet = CharSet.Ansi）]
public static extern bool
DelphiFunction（int inputInt，string inputString，
out int outputInt，
int outputStringBufferSize，ref string outputStringBuffer，
int errorMsgBufferSize，ref string errorMsgBuffer）;
static void Main（string [] args）
{
int inputInt = 1;
string inputString =这是一个测试;
int outputInt;
const int stringBufferSize = 1024;
var outputStringBuffer = new String（'\x00'，stringBufferSize）;
var errorMsgBuffer = new String（'\x00'，stringBufferSize）;
if（！DelphiFunction（inputInt，inputString，
out outputInt，
stringBufferSize，ref outputStringBuffer，
stringBufferSize，ref errorMsgBuffer））
Console.WriteLine （Error = \{0} \，errorMsgBuffer）;
else
Console.WriteLine（outputInt = {0}，outputString = \{1} \，
outputInt，outputStringBuffer）;
Console.Write（按回车：）;
Console.ReadLine（）;
}
}
}
这里还有一个额外的类显示如何动态加载DLL（对于长行而言）：
using System;
使用System.Runtime.InteropServices;
命名空间CsharpApp
{
静态类DynamicLinking
{
[DllImport（kernel32.dll，EntryPoint =LoadLibrary）]
static extern int LoadLibrary（[MarshalAs（UnmanagedType.LPStr）] string lpLibFileName）;
[DllImport（kernel32.dll，EntryPoint =GetProcAddress）]
static extern IntPtr GetProcAddress（int hModule，[MarshalAs（UnmanagedType.LPStr）] string lpProcName）;
[DllImport（kernel32.dll，EntryPoint =FreeLibrary）]
static extern bool FreeLibrary（int hModule）;
[UnmanagedFunctionPointer（CallingConvention.StdCall，CharSet = CharSet.Ansi）]
委托bool DelphiFunction（int inputInt，string inputString，
out int outputInt，
int outputStringBufferSize ，ref string outputStringBuffer，
int errorMsgBufferSize，ref string errorMsgBuffer）;
public static void CallDelphiFunction（int inputInt，string inputString，
out int outputInt，out string outputString）
{
const string dllName =DelphiLib.dll;
const string functionName =DelphiFunction;
int libHandle = LoadLibrary（dllName）;
if（libHandle == 0）
throw new异常（string.Format（无法加载库\{0} \，dllName））;
try
{
var delphiFunctionAddress = GetProcAddress（libHandle，functionName）;
if（delphiFunctionAddress == IntPtr.Zero）
throw new异常（string.Format（can not find function \{0} \in library \{1} \ ，functionName，dllName））;
var delphiFunction =（DelphiFunction）Marshal.GetDelegateForFunctionPointer（delphiFunctionAddress，typeof（DelphiFunction））;
const int stringBufferSize = 1024;
var outputStringBuffer = new String（'\x00'，stringBufferSize）;
var errorMsgBuffer = new String（'\x00'，stringBufferSize）;
if（！delphiFunction（inputInt，inputString，out outputInt，
stringBufferSize，ref outputStringBuffer，
stringBufferSize，ref errorMsgBuffer））
throw new Exception（errorMsgBuffer）;
outputString = outputStringBuffer;
}
finally
{
FreeLibrary（libHandle）;
}
}
}
}
Dan
EDIT: I've posted a better implementation of this, below. I left this here so the responses would make sense.
I've done numerous searches for the correct method for writing a DLL in Delphi, and being able to call it from C#, passing and returning strings. A lot of the information was incomplete or incorrect. After much trial and error, I found the solution.
This was compiled using Delphi 2007 and VS 2010. I suspect it will work fine in other versions as well.
Here's the Delphi code. Remember to include version information in the project.
library DelphiLibrary;
uses SysUtils;
// Compiled using Delphi 2007.
// NOTE: If your project doesn't have version information included, you may
// receive the error "The "ResolveManifestFiles" task failed unexpectedly"
// when compiling the C# application.
{$R *.res}
// Example function takes an input integer and input string, and returns
// inputInt + 1, and inputString + ' ' + IntToStr(outputInt) as output
// parameters. If successful, the return result is nil (null), otherwise it is
// the exception message string.
// NOTE: I've posted a better version of this below. You should use that instead.
function DelphiFunction(inputInt : integer; inputString : PAnsiChar;
out outputInt : integer; out outputString : PAnsiChar)
: PAnsiChar; stdcall; export;
var s : string;
begin
outputInt := 0;
outputString := nil;
try
outputInt := inputInt + 1;
s := inputString + ' ' + IntToStr(outputInt);
outputString := PAnsiChar(s);
Result := nil;
except
on e : exception do Result := PAnsiChar(e.Message);
end;
end;
// I would have thought having "export" at the end of the function declartion
// (above) would have been enough to export the function, but I couldn't get it
// to work without this line also.
exports DelphiFunction;
begin
end.
Here's the C# code:
using System;
using System.Runtime.InteropServices;
namespace CsharpApp
{
class Program
{
// I added DelphiLibrary.dll to my project (NOT in References, but
// "Add existing file"). In Properties for the dll, I set "BuildAction"
// to None, and "Copy to Output Directory" to "Copy always".
// Make sure your Delphi dll has version information included.
[DllImport("DelphiLibrary.dll",
CallingConvention = CallingConvention.StdCall,
CharSet = CharSet.Ansi)]
public static extern
string DelphiFunction(int inputInt, string inputString,
out int outputInt, out string outputString);
static void Main(string[] args)
{
int inputInt = 1;
string inputString = "This is a test";
int outputInt;
string outputString;
// NOTE: I've posted a better version of this below. You should use that instead.
Console.WriteLine("inputInt = {0}, intputString = \"{1}\"",
inputInt, inputString);
var errorString = DelphiFunction(inputInt, inputString,
out outputInt, out outputString);
if (errorString != null)
Console.WriteLine("Error = \"{0}\"", errorString);
else
Console.WriteLine("outputInt = {0}, outputString = \"{1}\"",
outputInt, outputString);
Console.Write("Press Enter:");
Console.ReadLine();
}
}
}
I hope this information helps someone else to not have to pull their hair out as much as I did.
解决方案
Based on responses to my post, I have created a new example that uses string buffers for the returned strings, instead of just returning PAnsiChars.
Delphi DLL source:
library DelphiLibrary;
uses SysUtils;
// Compiled using Delphi 2007.
// NOTE: If your project doesn't have version information included, you may
// receive the error "The "ResolveManifestFiles" task failed unexpectedly"
// when compiling the C# application.
{$R *.res}
// A note on returing strings. I had originally written this so that the
// output string was just a PAnsiChar. But several people pointed out that
// since Delphi strings are reference-counted, this was a bad idea since the
// memory for the string could get overwritten before it was used.
//
// Because of this, I re-wrote the example so that you have to pass a buffer for
// the result strings. I saw some examples of how to do this, where they
// returned the actual string length also. This isn't necessary, because the
// string is null-terminated, and in fact the examples themselves never used the
// returned string length.
// Example function takes an input integer and input string, and returns
// inputInt + 1, and inputString + ' ' + IntToStr(outputInt). If successful,
// the return result is true, otherwise errorMsgBuffer contains the the
// exception message string.
function DelphiFunction(inputInt : integer;
inputString : PAnsiChar;
out outputInt : integer;
outputStringBufferSize : integer;
var outputStringBuffer : PAnsiChar;
errorMsgBufferSize : integer;
var errorMsgBuffer : PAnsiChar)
: WordBool; stdcall; export;
var s : string;
begin
outputInt := 0;
try
outputInt := inputInt + 1;
s := inputString + ' ' + IntToStr(outputInt);
StrLCopy(outputStringBuffer, PAnsiChar(s), outputStringBufferSize-1);
errorMsgBuffer[0] := #0;
Result := true;
except
on e : exception do
begin
StrLCopy(errorMsgBuffer, PAnsiChar(e.Message), errorMsgBufferSize-1);
Result := false;
end;
end;
end;
// I would have thought having "export" at the end of the function declartion
// (above) would have been enough to export the function, but I couldn't get it
// to work without this line also.
exports DelphiFunction;
begin
end.
C# Code:
using System;
using System.Runtime.InteropServices;
namespace CsharpApp
{
class Program
{
// I added DelphiLibrary.dll to my project (NOT in References, but
// "Add existing file"). In Properties for the dll, I set "BuildAction"
// to None, and "Copy to Output Directory" to "Copy always".
// Make sure your Delphi dll has version information included.
[DllImport("DelphiLibrary.dll",
CallingConvention = CallingConvention.StdCall,
CharSet = CharSet.Ansi)]
public static extern bool
DelphiFunction(int inputInt, string inputString,
out int outputInt,
int outputStringBufferSize, ref string outputStringBuffer,
int errorMsgBufferSize, ref string errorMsgBuffer);
static void Main(string[] args)
{
int inputInt = 1;
string inputString = "This is a test";
int outputInt;
const int stringBufferSize = 1024;
var outputStringBuffer = new String('\x00', stringBufferSize);
var errorMsgBuffer = new String('\x00', stringBufferSize);
if (!DelphiFunction(inputInt, inputString,
out outputInt,
stringBufferSize, ref outputStringBuffer,
stringBufferSize, ref errorMsgBuffer))
Console.WriteLine("Error = \"{0}\"", errorMsgBuffer);
else
Console.WriteLine("outputInt = {0}, outputString = \"{1}\"",
outputInt, outputStringBuffer);
Console.Write("Press Enter:");
Console.ReadLine();
}
}
}
And here's an additional class that shows how to load the DLL dynamically (sorry for the long lines):
using System;
using System.Runtime.InteropServices;
namespace CsharpApp
{
static class DynamicLinking
{
[DllImport("kernel32.dll", EntryPoint = "LoadLibrary")]
static extern int LoadLibrary([MarshalAs(UnmanagedType.LPStr)] string lpLibFileName);
[DllImport("kernel32.dll", EntryPoint = "GetProcAddress")]
static extern IntPtr GetProcAddress(int hModule, [MarshalAs(UnmanagedType.LPStr)] string lpProcName);
[DllImport("kernel32.dll", EntryPoint = "FreeLibrary")]
static extern bool FreeLibrary(int hModule);
[UnmanagedFunctionPointer(CallingConvention.StdCall, CharSet = CharSet.Ansi)]
delegate bool DelphiFunction(int inputInt, string inputString,
out int outputInt,
int outputStringBufferSize, ref string outputStringBuffer,
int errorMsgBufferSize, ref string errorMsgBuffer);
public static void CallDelphiFunction(int inputInt, string inputString,
out int outputInt, out string outputString)
{
const string dllName = "DelphiLib.dll";
const string functionName = "DelphiFunction";
int libHandle = LoadLibrary(dllName);
if (libHandle == 0)
throw new Exception(string.Format("Could not load library \"{0}\"", dllName));
try
{
var delphiFunctionAddress = GetProcAddress(libHandle, functionName);
if (delphiFunctionAddress == IntPtr.Zero)
throw new Exception(string.Format("Can't find function \"{0}\" in library \"{1}\"", functionName, dllName));
var delphiFunction = (DelphiFunction)Marshal.GetDelegateForFunctionPointer(delphiFunctionAddress, typeof(DelphiFunction));
const int stringBufferSize = 1024;
var outputStringBuffer = new String('\x00', stringBufferSize);
var errorMsgBuffer = new String('\x00', stringBufferSize);
if (!delphiFunction(inputInt, inputString, out outputInt,
stringBufferSize, ref outputStringBuffer,
stringBufferSize, ref errorMsgBuffer))
throw new Exception(errorMsgBuffer);
outputString = outputStringBuffer;
}
finally
{
FreeLibrary(libHandle);
}
}
}
}
-Dan
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