在基于MFC对话框的应用程序中写入文本文件 [英] Writing into text file in mfc dialog based application

问题描述

大家好，

我正在做一个基于mfc对话框的应用程序.在我的对话框中，我有组合框，编辑控件.现在我必须阅读那些框中的文本并将其写入文件中.为此，我使用的结构将是这样，

结构配置
{
浮动版本号;
字符名称[20];
int n_tcp;
}
struct config myfile;

写入Char值没有问题，但是在将整数写入文本文件时出现类似这样的未知符号''?''，我正在使用以下代码写入文本文件.

CFile file_object(filepath，CFile :: modeCreate | CFile :: modeWrite);
file_object.Write(reinterpret_cast(&myfile)，sizeof(config));

还有其他方法可以在结构中正确写入整数值吗.请指导我，

Shiva ..

Hello everyone,

I am doing a mfc dialog based application.In my dialog box, i have combo boxes,edit controls.Now i have to read the text in those boxes and write it into a file.For this i use a structure will be like this,

struct config
{
float version_number;
char name[20];
int n_tcp;
}
struct config myfile;

There is no problem with writing Char value.But i am getting some unknown symbols '''' like this when writing integer into text file.I am using the following code to write into text file.

CFile file_object(filepath,CFile::modeCreate|CFile::modeWrite);
file_object.Write(reinterpret_cast(&myfile),sizeof(config));

Is there anyother way to write integer value in structure properly..Pls guide me,

Shiva..

推荐答案

由于您正在文件中写入整个结构，因此该结构以字节序列而不是字符串/文本的形式进入文件.例如，如果将int(4字节)写入文件，则不会看到整数的实际值，而是一些奇怪的值.不用担心，您不必担心.读取整数(按字节顺序)时，可以正确获取整数.
简而言之，无论整数值如何，您都要写入4个字节.然后读取4个字节，就可以得到int的值.


同样，您正在编写整个结构(28字节)，您肯定会看到这些字符.当您读取相同结构的28字节序列并将其类型转换为相同结构时，您将获得相同的值！

您应该使用memset/ZeroMemory将结构设置为null以获得清晰的图片.在Visual Studio中(在BINARY EDITOR中)打开文件.

Since you are writing whole structure in file, the structure goes into file as sequence of bytes, not as string/text. For example if you write an int (4-byte) into file, you will NOT see the actual value of integer, but some bizarre value. Dont worry, and you need not to worry. When you read the integer, in sequence-of-bytes form, you get your integer properly.
In short, you write 4 bytes, irrespective of the value of integer. Then you read 4-bytes, and you get value in int.


Similarly, you are writing the whole structure (which is 28 bytes), you''d definitely see those characters. When you read the same structure are sequence of 28-bytes, and typecast into same structure, you''d get the same values!

You should set the structure to null,with memset/ZeroMemory to get the clear picture. Open file in Visual Studio (in BINARY EDITOR).

如果您需要将数值写为人类可读的文本，则可以使用CString和CStdioFile类，例如实例:

If you need to write the numeric values as human-readable text than you may use use CString and CStdioFile classes, for instance:

CStdioFile file_object(filepath,CFile::modeCreate|CFile::modeWrite);
CString sValue;
sValue.Format(_T("%f"), myfile.version_number);
file_object.WriteString(","); // field separator
file_object.WriteString(myfile.name);
file_object.WriteString(","); // field separator
sValue.Format(_T("%d"), myfile.n_tcp);
file_object.WriteString("\n"); // record separator
...

:)

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