vc中常用文件操作（一）

　　一.将信息写入.INI文件中.

　　1.所用的WINAPI函数原型为:

BOOL WritePrivateProfileString(
LPCTSTR lpAppName,
LPCTSTR lpKeyName,
LPCTSTR lpString,
LPCTSTR lpFileName
);

　　其中各参数的意义:

　　　LPCTSTR lpAppName 是INI文件中的一个字段名.

　　　LPCTSTR lpKeyName 是lpAppName下的一个键名,通俗讲就是变量名.

　　　LPCTSTR lpString 是键值,也就是变量的值,不过必须为LPCTSTR型或CString型的.

　　　LPCTSTR lpFileName 是完整的INI文件名.

　　2.具体使用方法:设现有一名学生,需把他的姓名和年龄写入 c:/stud/student.ini 文件中.

CString strName,strTemp;
int nAge;
strName="张三";
nAge=12;
::WritePrivateProfileString("StudentInfo","Name",strName,"c://stud//student.ini");

　　此时c:/stud/student.ini文件中的内容如下:

　　　[StudentInfo]
　　　Name=张三

　　3.要将学生的年龄保存下来,只需将整型的值变为字符型即可:

strTemp.Format("%d",nAge);
::WritePrivateProfileString("StudentInfo","Age",strTemp,"c://stud//student.ini");

　二.将信息从INI文件中读入程序中的变量.

　　1.所用的WINAPI函数原型为:

DWORD GetPrivateProfileString(
LPCTSTR lpAppName,
LPCTSTR lpKeyName,
LPCTSTR lpDefault,
LPTSTR lpReturnedString,
DWORD nSize,
LPCTSTR lpFileName
);

　　其中各参数的意义:

　　　前二个参数与 WritePrivateProfileString中的意义一样.

　　　lpDefault : 如果INI文件中没有前两个参数指定的字段名或键名,则将此值赋给变量.

　　　lpReturnedString : 接收INI文件中的值的CString对象,即目的缓存器.

　　　nSize : 目的缓存器的大小.

　　　lpFileName : 是完整的INI文件名.

　　2.具体使用方法:现要将上一步中写入的学生的信息读入程序中.

CString strStudName;
int nStudAge;
GetPrivateProfileString("StudentInfo","Name","默认姓名",strStudName.GetBuffer(MAX_PATH),MAX_PATH,"c://stud//student.ini");

　　执行后 strStudName 的值为:"张三",若前两个参数有误,其值为:"默认姓名".

　　3.读入整型值要用另一个WINAPI函数:

UINT GetPrivateProfileInt(
LPCTSTR lpAppName,
LPCTSTR lpKeyName,
INT nDefault,
LPCTSTR lpFileName
);

　　这里的参数意义与上相同.使用方法如下:

nStudAge=GetPrivateProfileInt("StudentInfo","Age",10,"c://stud//student.ini");

三.循环写入多个值,设现有一程序,要将最近使用的几个文件名保存下来,具体程序如下:

　　1.写入:

CString strTemp,strTempA;
int i;
int nCount=6;
file://共有6个文件名需要保存
for(i=0;i {strTemp.Format("%d",i);
strTempA=文件名;
file://文件名可以从数组,列表框等处取得.
::WritePrivateProfileString("UseFileName","FileName"+strTemp,strTempA,
"c://usefile//usefile.ini");
}
strTemp.Format("%d",nCount);
::WritePrivateProfileString("FileCount","Count",strTemp,"c://usefile//usefile.ini");
file://将文件总数写入,以便读出.

　　2.读出:

nCount=::GetPrivateProfileInt("FileCount","Count",0,"c://usefile//usefile.ini");
for(i=0;i {strTemp.Format("%d",i);
strTemp="FileName"+strTemp;
::GetPrivateProfileString("CurrentIni",strTemp,"default.fil", strTempA.GetBuffer(MAX_PATH),MAX_PATH,"c://usefile//usefile.ini");

file://使用strTempA中的内容.

}

　　补充四点:
　　　1.INI文件的路径必须完整,文件名前面的各级目录必须存在,否则写入不成功,该函数返回 FALSE 值.
　　　2.文件名的路径中必须为 // ,因为在VC++中, // 才表示一个 / .
　　　3.也可将INI文件放在程序所在目录,此时 lpFileName 参数为: ".//student.ini".

vc操作常用文件操作（三）CFileExample

CFile is the class used for handling Files in MFC. This class can be used for creating, reading, writing and modifying files. It directly provides unbuffered, binary disk input/output services, and it indirectly supports text files and memory files through its derived classes.

CFile - Creating a File:

There are two ways of creating files. One way is to instantiate the CFile object with the file path. This creates the file. The second way is to call the Open function. This also creates the file.

CFile cfile_object( "c://test//codersource_cfile_example.txt", CFile::modeCreate|CFile:: modeReadWrite);

CFile cfile_object;
cfile_object.Open( "c://test//codersource_cfile_example.txt", CFile::modeCreate|CFile:: modeReadWrite);

The first parameter to both the functions (CFile() constructor and Open()) is the physical path of the file in the disk.The second parameter is an enumerated constant. This specifies the mode of opening the file object. The above constantsmodeCreate implies "create a new file" and modeReadWrite means "open the file for both reading and writing".

If the file is opened without specifying the mode constant shareDenyNone, this file can be opened in read mode byother programs. This feature will be necessary for text files, logs created by programs. For creating text files we useCFile::typeText and for binary files CFile::typeBinary.

CFile - Writing to a File:

The function Write is used to write data to the files. The sample code is as follows.

CFile cfile_object;
cfile_object.Open( "c://test//codersource_cfile_example.txt", CFile::modeCreate|CFile::modeWrite);

char szSampleText[100];
strcpy(szSampleText, "Sample Text for CFile Write function Example");
cfile_object.Write (szSampleText,100);

If there is any need to write text line by line, it is better to use the class CStdioFile.

CFile - Reading from a file:

The function Read is used to read data from files. The sample code is,

CFile cfile_object;
cfile_object.Open( "c://test//codersource_cfile_example.txt", CFile::modeCreate|CFile::modeWrite);

char szSampleText[100];
UINT lBytesRead = cfile_object.Read (szSampleText,100);

The function returns the number of bytes read from the file. The maximum number of characters read will be the secondparameter of the Read function.

CFile - closing the file:

The Close function is used to close the file. But the close function need not be called, as the destructor willautomatically call it if the file is open. So when the object goes out of scope, the destructor calls close function.

from: http://www.codersource.net/mfc_cfile.html