VC如何实现托拽

从程序外面，托动一个文件到应用程序界面，如何得到这个文件的路径并且激发一个处理消息？

另外，已经知道一个大字符串，现在要统计里面某一个字母的个数，如何统计？如果用While循环的话，要1分种，不现实，有没有什么速度快一点的方法？

谢谢 问题点数：50、回复次数：9Top

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1 楼DentistryDoctor（不在无聊中无奈，就在沉默中变态）回复于 2006-09-07 14:42:52 得分 15

1.An application that calls DragAcceptFiles with the fAccept parameter set to TRUE has identified itself as able to process the WM_DROPFILES message from File Manager.
在窗口创建时调用DragAcceptFiles(TRUE);然后程序处理WM_DROPFILE消息
2.循环要一秒钟,什么字符串这么大?CString.Find?Top

2 楼SoLike（思危）回复于 2006-09-07 14:43:00 得分 0

在窗口中响应 WM_DROPFILES 消息Top

3 楼baojian88888（机器人）回复于 2006-09-07 14:45:15 得分 5

拖文件：
先给窗口设置WS_EX_ACCEPTFILES风格，然后处理 WM_DROPFILES 消息Top

4 楼SoLike（思危）回复于 2006-09-07 14:45:20 得分 20

Dragging Files

Dragging Files can be supported relatively easily as follows

* Add a OnDropFiles(HDROP hDropInfo) handler to your Dialog. You'll probably have to add this manually, as ClassWizard doesn't seen to support the WM_DROPFILES message for dialogs.

Make the following changes

1) In your .h file add the OnDropFiles to the AFX_MSG section

// Generated message map functions
//{{AFX_MSG(A2hDialog)
...
afx_msg void OnDropFiles(HDROP hDropInfo);
...
//}}AFX_MSG
DECLARE_MESSAGE_MAP()


2) In your .cpp file add the ON_WM_DROPFILES() handler to the AFX_MSG_MAP section

BEGIN_MESSAGE_MAP(MyDialog, CDialog)
//{{AFX_MSG_MAP(MyDialog)
...
ON_WM_DROPFILES()
...
//}}AFX_MSG_MAP
END_MESSAGE_MAP()


Strangely, after doing (1) and (2) the results become visible in the ClassWizard.

3)
Use ClassWizard to add an OnCreate() handler to your dialog. in this add the call

this->DragAcceptFiles(TRUE);

This enables Drag and drop of files on your Dialog's window. You can check this by dragging files over your Window. If the cursor is a "no entry" sign (circle with a line through it) it's not working. If the cursor changes to a file/folder icon with a "+" on it, you're in business.

4) Manually add the OnDropFiles method to look something as follows :-

void MyDialog::OnDropFiles(HDROP hDropInfo)
{

HDROP m_hDropInfo = hDropInfo;
CString Filename;

if (m_hDropInfo) {

int iFiles = DragQueryFile(m_hDropInfo, (UINT)-1, NULL, 0);

for (int i=0; i<ifiles; i++) {

char* pFilename = Filename.GetBuffer(_MAX_PATH);
DragQueryFile(m_hDropInfo, i, pFilename, _MAX_PATH);

// do whatever...

} // for each files...
} // if DropInfo

DragFinish(m_hDropInfo);

m_hDropInfo = 0;

} // End of OnDropFiles

Top

5 楼dch4890164（巴拉克）回复于 2006-09-07 14:45:32 得分 0

楼上两位正确，鉴定完毕，飘过！Top

6 楼kilojin（梅子黄时雨，我在编程时）回复于 2006-09-07 14:47:42 得分 0

一个Log文件，大约10M，现在要统计里面某一个类别Log的数量，LogKey是有的，不过，太多，Find 循环统计，要很长时间
我记得Ultraedit里面，有这个功能，一下子就统计出来了，不知道如何实现的
Top

7 楼Mackz（在相互）回复于 2006-09-07 16:40:10 得分 5

主要的时间应该在读取文件上了，映射一下。比较必需要循环的，提高效率的方法是在查找上，比如模式匹配。Top

8 楼codewarrior（会思考的草）回复于 2006-09-07 16:59:23 得分 5

关于拖动可以看我的blog.
速度快主要是要优化算法,使用映射文件可能会好一点.Top

9 楼immc1979（毛毛虫）回复于 2006-12-06 14:09:31 得分 0

标记一个