Windows 文件的创建打开和关闭

Posted 2022-03-02 胡刚2021

点击跳转到视频教程

1.创建一个新的空白文件
代码：
主要配置 CreateFile 的参数为 CREATE_ALWAYS

#include<windows.h>
#include<tchar.h>
int WINAPI _tWinMain(HINSTANCE hinstance, HINSTANCE hPreInstance, LPTSTR lpCmdLine, int nShowCmd) 

	HANDLE hFile = CreateFile(_T("D:\\\\123.txt"), GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
	if (hFile != INVALID_HANDLE_VALUE)
	
		MessageBox(NULL, _T("创建文件成功"), _T("tip"), MB_OK);
	
	
	return 0;

2.打开一个已经存在的文件
代码：
主要配置 CreateFile 的参数为 OPEN_EXISTING

#include<windows.h>
#include<tchar.h>
int WINAPI _tWinMain(HINSTANCE hinstance, HINSTANCE hPreInstance, LPTSTR lpCmdLine, int nShowCmd) 

	/*HANDLE hFile = CreateFile(_T("D:\\\\123.txt"), GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
	if (hFile != INVALID_HANDLE_VALUE)
	
		MessageBox(NULL, _T("创建文件成功"), _T("tip"), MB_OK);
	*/

	HANDLE hFile = CreateFile(_T("D:\\\\123.txt"), GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
	if (hFile != INVALID_HANDLE_VALUE)
	
		MessageBox(NULL, _T("打开文件成功"), _T("tip"), MB_OK);
	
	else
	
		MessageBox(NULL, _T("打开文件失败"), _T("tip"), MB_OK);
	
	return 0;

3.打开一个文件，如果文件存在，则打开；如果文件不存在，则创建该文件，然后打开
代码：
主要配置 CreateFile 的参数为 OPEN_ALWAYS

#include<windows.h>
#include<tchar.h>
int WINAPI _tWinMain(HINSTANCE hinstance, HINSTANCE hPreInstance, LPTSTR lpCmdLine, int nShowCmd) 

	/*HANDLE hFile = CreateFile(_T("D:\\\\123.txt"), GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
	if (hFile != INVALID_HANDLE_VALUE)
	
		MessageBox(NULL, _T("创建文件成功"), _T("tip"), MB_OK);
	*/

	/*HANDLE hFile = CreateFile(_T("D:\\\\123.txt"), GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
	if (hFile != INVALID_HANDLE_VALUE)
	
		MessageBox(NULL, _T("打开文件成功"), _T("tip"), MB_OK);
	
	else
	
		MessageBox(NULL, _T("打开文件失败"), _T("tip"), MB_OK);
	*/

	HANDLE hFile = CreateFile(_T("D:\\\\123.txt"), GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ, NULL, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
	if (hFile != INVALID_HANDLE_VALUE)
	
		MessageBox(NULL, _T("打开文件成功"), _T("tip"), MB_OK);
	
	else
	
		MessageBox(NULL, _T("打开文件失败"), _T("tip"), MB_OK);
	
	return 0;

4.打开一个文件，如果该文件存在，则清空内容；如果该文件不存在，则创建该文件
代码：
主要配置 CreateFile 的参数为 CREATE_ALWAYS

#include<windows.h>
#include<tchar.h>
int WINAPI _tWinMain(HINSTANCE hinstance, HINSTANCE hPreInstance, LPTSTR lpCmdLine, int nShowCmd) 

	/*HANDLE hFile = CreateFile(_T("D:\\\\123.txt"), GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
	if (hFile != INVALID_HANDLE_VALUE)
	
		MessageBox(NULL, _T("创建文件成功"), _T("tip"), MB_OK);
	*/

	/*HANDLE hFile = CreateFile(_T("D:\\\\123.txt"), GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
	if (hFile != INVALID_HANDLE_VALUE)
	
		MessageBox(NULL, _T("打开文件成功"), _T("tip"), MB_OK);
	
	else
	
		MessageBox(NULL, _T("打开文件失败"), _T("tip"), MB_OK);
	*/

	/*HANDLE hFile = CreateFile(_T("D:\\\\123.txt"), GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ, NULL, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
	if (hFile != INVALID_HANDLE_VALUE)
	
		MessageBox(NULL, _T("打开文件成功"), _T("tip"), MB_OK);
	
	else
	
		MessageBox(NULL, _T("打开文件失败"), _T("tip"), MB_OK);
	*/

	HANDLE hFile = CreateFile(_T("D:\\\\123.txt"), GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
	if (hFile != INVALID_HANDLE_VALUE)
	
		MessageBox(NULL, _T("打开文件成功"), _T("tip"), MB_OK);
	
	else
	
		MessageBox(NULL, _T("打开文件失败"), _T("tip"), MB_OK);
	
	return 0;

5.关闭文件

CloseHandle(hFile);

代码：
只有打开成功的时候才关闭句柄，打开失败的时候句柄 hFile 不需要关闭

#include<windows.h>
#include<tchar.h>
int WINAPI _tWinMain(HINSTANCE hinstance, HINSTANCE hPreInstance, LPTSTR lpCmdLine, int nShowCmd) 

	HANDLE hFile = CreateFile(_T("D:\\\\123.txt"), GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
	if (hFile != INVALID_HANDLE_VALUE)
	
		// 只有打开成功的时候才关闭句柄，打开失败的时候hFile不需要关闭
		CloseHandle(hFile);
		MessageBox(NULL, _T("打开文件成功"), _T("tip"), MB_OK);
	
	else
	
		MessageBox(NULL, _T("打开文件失败"), _T("tip"), MB_OK);
	
	return 0;