在c＃代码中导入DLL函数 [英] Importing DLL functions in c# code

问题描述

我有一个DLL，我希望在我的c＃代码中使用它的功能以下是该DLL的功能：

  extern    C 
 
 {
 
  __ declspec （ dllimport ） const   char  *  __ stdcall  ZAJsonRequestA（ const   char  * szReq）; 
 
  __ declspec （ dllimport ） const   wchar_t  *  __ stdcall  ZAJsonRequestW（ const   wchar_t  * szReq）; 
 
  __ declspec （ dllimport ） const  BSTR  __ stdcall  ZAJsonRequestBSTR（BSTR sReq）; 
 
} 

对于第一个函数，我使用了语法下面：



我的声明是这样的：

[DllImport（FANselect.dll，EntryPoint =ZAJsonRequestA）]

private static extern string ZAJsonRequestA（string szReq）;



我尝试使用以下方法调用它：

string sResult = ZAJsonRequestA（sRequest）;



当我尝试调用该函数时，它会离开块并且以下其他语句不会被执行。



任何人都可以告诉我，我在这里做错了什么？

如何在c＃项目中使用它，因为这个dll似乎是用其他语言？

解决方案

一般来说，进行ap / invoke导入并不复杂。您可以在此处找到更多信息，甚至可以找到现成的导入产品： http://www.pinvoke.net/ [ ^ ]

您可以使用一些工具来帮助您构建导入签名。像这两个：

http://clrinterop.codeplex.com/releases/view/17579 [ ^ ]

http://www.red-gate.com/products/dotnet-development/pinvoke/ [ ^ ]

所以，最后我得到了解决方案。



声明如下：



[DllImport（FANselect.dll，CallingConvention = CallingConvention.StdCall，

EntryPoint =ZAJsonRequestA，ExactSpelling = false）]



private static extern IntPtr ZAJsonRequestA（[MarshalAs（UnmanagedType.LPStr）] StringBuilder szReq）;





要调用它：



StringBuilder sbuilder = new StringBuilder（）;

sbuilder.Append（inputBox.Text）;

string sResult = Marshal.PtrToStringAnsi（ZAJsonRequestA（ sbuilder））;



感谢您的时间！

I have a DLL, whose functions i want to use in my c# code Here are the functions of that DLL :

extern "C" 

{

 __declspec(dllimport) const char* __stdcall ZAJsonRequestA(const char *szReq);

__declspec(dllimport) const wchar_t* __stdcall ZAJsonRequestW(const wchar_t *szReq);

__declspec(dllimport) const BSTR __stdcall ZAJsonRequestBSTR(BSTR sReq); 

}

For the first function, i have used the syntax below :

My declaration is like this :
[DllImport("FANselect.dll", EntryPoint = "ZAJsonRequestA")]
private static extern string ZAJsonRequestA(string szReq);

and i try to invoke it using :
string sResult = ZAJsonRequestA(sRequest);

When i try to invoke the function, it goes out of the block and the following other statements donot get executed.

Can anyone tell me, what i am doing wrong here ?
how to use it in c# project, as this dll seems to be in other language ?

解决方案

Making a p/invoke import is not complicated in general. You can find more info and even find ready-made imports here: http://www.pinvoke.net/[^]
You can use some tools to help you build import signatures. Like these two:
http://clrinterop.codeplex.com/releases/view/17579[^]
http://www.red-gate.com/products/dotnet-development/pinvoke/[^]

So, finally i got the solution.

the declaration is like :

[DllImport("FANselect.dll", CallingConvention = CallingConvention.StdCall,
EntryPoint = "ZAJsonRequestA", ExactSpelling=false)]

private static extern IntPtr ZAJsonRequestA([MarshalAs(UnmanagedType.LPStr)]StringBuilder szReq);


To invoke it :

StringBuilder sbuilder = new StringBuilder();
sbuilder.Append(inputBox.Text);
string sResult = Marshal.PtrToStringAnsi(ZAJsonRequestA(sbuilder));

Thanks for your time guys!

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