Get C string into C#

[Aku]

Hi,

My C# app is talking to a unmanaged Win32 DLL - the DLL is producing a
string in a char array.
I need to get that string information into my C# code - how to do it?
Thanks!

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[LEBRUN Thomas]

You just need to get the char array and transform it on a string.

Create a little function for this taks.

Tom.

"Aku" wrote:

Hi,

My C# app is talking to a unmanaged Win32 DLL - the DLL is producing a
string in a char array.
I need to get that string information into my C# code - how to do it?
Thanks!

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Don't just participate in USENET...get rewarded for it!

[Aku]

Thomas,
Please elaborate - I don't know how to do it ... .
Here are some of the relevant snippets of my code:

Unmgd DLL code:
SIMPLEDLL_API char* getname(InfStruct* A_info)
char string[50];
..... // data gets into the array
return string;
//----------------------------------------------
SIMPLEDLL_API char* fnstrSimpleDLL(void)
{
char* mystring;
mystring = getname(&InfBuff);
...
return mystring;
}
//-----------------------------------------------

Managed part:
[DllImport("SimpleDLL.dll", EntryPoint="fnstrSimpleDLL")]
public static extern string fnstrSimpleDLL();

//---------------
private void button1_Click(object sender, System.EventArgs e)
{
int retval = fnSimpleDLL();//Invoke the DLL function
...
string x = Convert.ToString(fnstrSimpleDLL());
// this doesnot work ...!
}
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[Aku]

Thomas,
Please elaborate - I don't know how to do it ... .
Here are some of the relevant snippets of my code:

Unmgd DLL code:
SIMPLEDLL_API char* getname(InfStruct* A_info)
char string[50];
..... // data gets into the array
return string;
//----------------------------------------------
SIMPLEDLL_API char* fnstrSimpleDLL(void)
{
char* mystring;
mystring = getname(&InfBuff);
...
return mystring;
}
//-----------------------------------------------

Managed part:
[DllImport("SimpleDLL.dll", EntryPoint="fnstrSimpleDLL")]
public static extern string fnstrSimpleDLL();

//---------------
private void button1_Click(object sender, System.EventArgs e)
{
int retval = fnSimpleDLL();//Invoke the DLL function
...
string x = Convert.ToString(fnstrSimpleDLL());
// this doesnot work ...!
}
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[Nicholas Paldino [.NET/C# MVP]]

Aku,

You will most likely want to use one of the static methods on the
Marshal class. Can you give the original declaration of the function in the
C DLL? You might not have to do much more than attribute the method
declaration correctly.
--
- Nicholas Paldino [.NET/C# MVP]
- mv*@spam.guard.caspershouse.com

"Aku" <an*******@devdex.com> wrote in message
news:OJ*************@TK2MSFTNGP10.phx.gbl...

Hi,

My C# app is talking to a unmanaged Win32 DLL - the DLL is producing a
string in a char array.
I need to get that string information into my C# code - how to do it?
Thanks!

*** Sent via Devdex http://www.devdex.com ***
Don't just participate in USENET...get rewarded for it!

[Nicholas Paldino [.NET/C# MVP]]

Aku,

You will most likely want to use one of the static methods on the
Marshal class. Can you give the original declaration of the function in the
C DLL? You might not have to do much more than attribute the method
declaration correctly.
--
- Nicholas Paldino [.NET/C# MVP]
- mv*@spam.guard.caspershouse.com

"Aku" <an*******@devdex.com> wrote in message
news:OJ*************@TK2MSFTNGP10.phx.gbl...

Hi,

My C# app is talking to a unmanaged Win32 DLL - the DLL is producing a
string in a char array.
I need to get that string information into my C# code - how to do it?
Thanks!

*** Sent via Devdex http://www.devdex.com ***
Don't just participate in USENET...get rewarded for it!

[Aku]

Nicholas,
Here is the requested information - hopefully you can help me out --
Thanks!
=================
// SimpleDLL.cpp : Defines the entry point for the DLL application.

int retstatus;
InfStruct myInfo;
char string[50];

/*----------------------------------------------------------------------
-------------*/
BOOL APIENTRY DllMain( HANDLE hModule,
DWORD ul_reason_for_call,
LPVOID lpReserved
)

{
switch (ul_reason_for_call)
{
case DLL_PROCESS_ATTACH:
// Initialize once for each new process.
// Return FALSE to fail DLL load.
MessageBox(NULL,"SimpleDLL: DLL_PROCESS_ATTACH","SIMPLE DLL",MB_OK);
break;
...

case DLL_PROCESS_DETACH:
MessageBox(NULL,"SimpleDLL: DLL_PROCESS_DETACH","SIMPLE DLL",MB_OK);
break;
}
return TRUE;
}
/*--------------------------------------------------------------------*/
// This is an example of another exported function.
SIMPLEDLL_API char* fnstrSimpleDLL(void)
{
getname(&myInfo);

return string;
}
/*----------------------------------------------------------------------
-----------------*/
SIMPLEDLL_API char* getname(InfStruct* A_info)
{
retstatus = Read_Value_To_String(A_info->recordID, ATTRIB_NAME,
sizeof(string),string);
return string;
}
/*----------------------------------------------------------------------
-----------------*/

************************************************** **********************
*
//HEADER FILE:
#ifdef SIMPLEDLL_EXPORTS
#define SIMPLEDLL_API __declspec(dllexport)
#else
#define SIMPLEDLL_API __declspec(dllimport)
#endif
...

SIMPLEDLL_API int fnSimpleDLL(void); // Exported function
SIMPLEDLL_API char* fnstrSimpleDLL(void);

SIMPLEDLL_API char* getname(InfStruct* A_info);

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