＆QUOT;无法找到DLL＆QUOT名为[功能]切入点; （C ++到C＃类型转换） [英] "Unable to find an entry point named [function] in dll" (c++ to c# type conversion)

问题描述

我有一个来自第三方，这是用C ++编写的DLL。
下面是来自该dll文件的一些信息：

I have a dll which comes from a third party, which was written in C++. Here is some information that comes from the dll documentation:

//start documentation

RECO_DATA{
wchar_t Surname[200];
wchar_t Firstname[200];
}

说明：
数据结构，用于接收功能的结果。所有函数的结果将是
存储为统一code（UTF-8）。

Description: Data structure for receiving the function result. All function result will be stored as Unicode (UTF-8).

方法：

bool recoCHN_P_Name(char *imgPath,RECO_DATA *o_data);

输入：

char * imgPath

图像位置的这种情况的完整路径
        功能识别

the full path of the image location for this function to recognize

RECO_DATA * o_data

用于接收功能

数据对象
        结果。
    函数返回：
        真要是成功，否则为false会回来。

data object for receiving the function result. Function return: True if Success, otherwise false will return.

//end documentation

我想从我的C＃应用​​程序调用recoCHN_P_Name。为此，我想出了这个code：

I am trying to call the recoCHN_P_Name from my C# application. To this end, I came up with this code:

在code导入的DLL：

The code to import the dll:

    public class cnOCRsdk
{
    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
    public struct RECO_DATA{
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst=200)]
        public string FirstName;
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 200)]
        public string Surname;
        }

    [DllImport(@"cnOCRsdk.dll", EntryPoint="recoCHN_P_Name")]
    public static extern bool recoCHN_P_Name(byte[] imgPath, RECO_DATA o_data);
}

在code调用的函数：

The code to call the function:

            cnOCRsdk.RECO_DATA recoData = new cnOCRsdk.RECO_DATA();

        string path = @"C:\WINDOWS\twain_32\twainrgb.bmp";

        System.Text.ASCIIEncoding encoding = new System.Text.ASCIIEncoding();
        byte[] bytes = encoding.GetBytes(path);

        bool res = cnOCRsdk.recoCHN_P_Name(bytes, recoData);

和我得到错误的是
无法找到DLL'cnOCRsdk.dll名为'recoCHN_P_Name切入点。
我怀疑我是从C ++转换一个类型到C＃有一个错误。但究竟哪里...？

And the error I'm getting is ""Unable to find an entry point named 'recoCHN_P_Name' in DLL 'cnOCRsdk.dll'." I'm suspecting that I'm having an error in converting a type from C++ to C#. But where exactly ... ?

推荐答案

首先确保该功能实际出口：

First make sure the function is actually exported:

在Visual Studio命令提示符下，使用 DUMPBIN /出口whatever.dll

In the Visual Studio Command Prompt, use dumpbin /exports whatever.dll

这篇关于＆QUOT;无法找到DLL＆QUOT名为[功能]切入点; （C ++到C＃类型转换）的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！