如何从C＃调用C ++ DLL方法（将const char *作为输入参数和返回值） [英] How do I call a C++ dll method (having const char* as input params and return value) from C#

问题描述

我在C＃项目中添加了一个C ++库DLL。



我可以在C＃中调用下面的C ++方法。



以下是C ++中的方法定义

I have added a C++ library DLL in my C# project.

I am able to call the below method of C++ in my C#.

Below is method definition in C++

static  APICLIENT_API char* logIn1(const char* url, const char* loginID, const char* password, const char* salt, const char* timeStamp, const char* refererURL, int iterations)

我试图通过许多不同的方式在C＃中调用此方法但是找到了N. o运气。



我的最后一次尝试是

I tried to call this method in C# through many different ways but found No Luck.

My last try was

[DllImport(@"F:\bin\APIClient.dll", EntryPoint = "?logIn1@CAPIClient@API@@SAPADPBD00000H@Z", CallingConvention = CallingConvention.Cdecl)]
       [return: MarshalAs(UnmanagedType.LPStr)]
       public static extern string logIn1([MarshalAs(UnmanagedType.LPStr)]string a, [MarshalAs(UnmanagedType.LPStr)]string b, [MarshalAs(UnmanagedType.LPStr)]string c, [MarshalAs(UnmanagedType.LPStr)]string d, [MarshalAs(UnmanagedType.LPStr)]string e, [MarshalAs(UnmanagedType.LPStr)]string f, int g);


      string myStr= APICaller.logIn1("https://api.net/api/0.1/session/login","[e-mail]", "123123","", "1403762225", "https://api.net/", 4096);

但它也是没有用。（Visual Studio崩溃）



注意：如果C ++方法的数据类型很简单，如int或double，那么我就可以调用它们。 br />


请帮忙解决这个问题。

But it also didn't work.(Visual Studio crashes)

NOTE: If the datatypes of the C++ methods are simple like int or double then I am able to Call them .

Please help in resolving this.

推荐答案

一开始：不要使用完整的补丁。 dll属于你构建的输出目录（每个副本）



我多年来一直使用Stringbuilder对象进行这些任务。分配一些大小和大小作为第二个参数。

at first: dont use full pathes. The dll belongs in the output dir of your build (per copy)

I use Stringbuilder objects for these taskes for years. Allocated with some size and the size as second parameter.

StringBuilder sb = new StringBuilder(32);

MycppFunc( sb, 32 ); 

所以我知道我有多少空间。



阅读此 MSDN文章了解详情。重要的是使用认可的字符集。

So I know how many space I have.

Read this MSDN article for the details. Important is the use of the approbiate charset.

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