再问一个有关DLL声明的问题

Question

__int16  __stdcall  IC_Read(HANDLE idComDev,__int16 offset,__int16 len,unsigned char * databuffer);[DllImport("dllanme")]
public static extern short IC_Read(IntPtr idComDev,short offset,short len,StringBuilder databuffer);

Answer 1

看看这个例子
using System;
using System.Text;
using System.Runtime.InteropServices;public class blah
{
   [DllImport("C:\\temp\\test\\test.dll",
    CharSet=CharSet.Ansi,
    CallingConvention=CallingConvention.StdCall,
    SetLastError=true)]
    static extern void leggimet([In] String fName, 
                                [Out] StringBuilder buf, 
                                [In] UInt32 bufSize,
                                [Out]StringBuilder extrainfo, 
                                [Out]IntPtr resp);    public static void Main()
    {
        uint bufSize = 10;
        StringBuilder buf = new StringBuilder((int)bufSize);
        StringBuilder extraInfo = new StringBuilder(10); // Whatever is the max size of extrainfo.         
        int resp;        unsafe {
            leggimet("blah", buf, bufSize, extraInfo, new IntPtr(&resp));
        }        System.Console.WriteLine(buf);
        System.Console.WriteLine(extraInfo);
        System.Console.WriteLine(resp);
    }
}-- Example dll source ----#include <stdio.h>void __stdcall leggimet(const char* fname, 
                       unsigned char* buf,
                       unsigned long bufSizem,
                       char* extraInfo,
                       long* resp)
{
   printf("%s\n", fname);
   strcpy(buf, "Blah");
   strcpy(extraInfo, "Blah2");
   *resp = 10;
}