MultiByteToWideChar问题

[heidaizx]

#include <iostream>
#include <windows.h>
#include <cstring>
using namespace std;

int main()
{
	
	HANDLE hFiles = CreateFile("c:\\1.txt",GENERIC_READ|GENERIC_WRITE,FILE_SHARE_READ,
		NULL,CREATE_ALWAYS,FILE_ATTRIBUTE_NORMAL,NULL);

	char buffer[] = "hello world";
	DWORD numberWrite;
	BOOL bResult = WriteFile(hFiles,buffer,(DWORD)strlen(buffer)+1,&numberWrite,NULL);
	if(bResult == 0)
	{
		cout << "Error:" << GetLastError();
	}
	
	//cout << numberRead << endl;
	
	DWORD numberRead;
	char bufferTem[256];
	
	bResult = ReadFile(hFiles,bufferTem,-1,&numberRead,NULL);
	
	DWORD dwNum = MultiByteToWideChar(CP_ACP,0,bufferTem,-1,NULL,0);

	wchar_t *pwText;

	pwText = new wchar_t[dwNum];
	if(!pwText)
		delete []pwText;

	MultiByteToWideChar(CP_ACP,0,bufferTem,-1,pwText,dwNum);
	
	//cout << numberRead;
	//cout << bufferTem <<endl;

	wcout << pwText <<endl;
	return 0;
}

过程为新建文件，写入文件，读出文件内容，进行MultiByteToWideChar后仍然有乱码问题

[cnzdgs]

先setlocale(LC_ALL, "CHS");

[cnzdgs]

WriteFile之后，此时文件指针是在文件末尾，ReadFile读不到数据，要把文件指针设置到文件开头才行。

[danxuezx]

说一下您的环境？是unicode字符集吗？

[雪碧爱可乐]

//DWORD dwNum = MultiByteToWideChar(CP_ACP,0,bufferTem,-1,NULL,0);
//我怀疑上面的语句执行是否真的能成功返回准确的转化宽字符后的长度？
//你完全可以先分配完后再转化，如下：
wchar_t *pwText = new wchar_t[256];
if (NULL == MultiByteToWideChar(CP_ACP, 0, bufferTem, strlen(bufferTem), pwText, 256))
{
cout << "Error:" << GetLastError();
}
wcout << pwText <<endl;

[danxuezx]

我调试了一下，你的ReadFile返回了错误码998。

[qgw_2000]

ReadFile时有问题，你首先要把文件指针重置到文件开始处。
可以如下修改：

int main()
{

HANDLE hFiles = CreateFile("c:\\1.txt",GENERIC_READ|GENERIC_WRITE,FILE_SHARE_READ,
NULL,CREATE_ALWAYS,FILE_ATTRIBUTE_NORMAL,NULL);

char buffer[] = "hello world";
DWORD numberWrite;
BOOL bResult = WriteFile(hFiles,buffer,(DWORD)strlen(buffer)+1,&numberWrite,NULL);
if(bResult == 0)
{
cout << "Error:" << GetLastError();
}

//cout << numberRead << endl;

DWORD numberRead;
char bufferTem[256];

SetFilePointer(hFiles, 0, 0, FILE_BEGIN);
bResult = ReadFile(hFiles,bufferTem,256,&numberRead,NULL);

DWORD dwNum = MultiByteToWideChar(CP_ACP,0,bufferTem,-1,NULL,0);

wchar_t *pwText;

pwText = new wchar_t[dwNum];
if(!pwText)
delete []pwText;

MultiByteToWideChar(CP_ACP,0,bufferTem,-1,pwText,dwNum);

//cout << numberRead;
//cout << bufferTem <<endl;

wcout << pwText <<endl;
return 0;
}

[/code]

[lwx300]

6 楼正解。

[WillyWonka]

jf

[danxuezx]

ReadFile的参数3不能大于buffer的长度。将6楼中的ReadFile中的256改为-1同样失败。

[heidaizx]

谢谢了