subject_16320.htm

一些关于vc的问答

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序号：16320 发表者：lhbnj 发表日期：2002-09-27 11:58:03
<br>主题：请教benwolf：
<br>内容：<BR>　　如何在文档编辑器中的保存、另存为、打开中支持多种文件类型？<BR>虽说可以通过增加以下代码实现可打开多种文件类型：<BR>&nbsp;&nbsp;&nbsp;&nbsp;pDocTemplate = new CMultiDocTemplate(<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;IDR_SAMPLETYPE1,<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;RUNTIME_CLASS(CSampleDoc),<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;RUNTIME_CLASS(CChildFrame), // custom MDI child frame<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;RUNTIME_CLASS(CSampleView));<BR>&nbsp;&nbsp;&nbsp;&nbsp;AddDocTemplate(pDocTemplate);<BR>可是，在保存及另存中仍无能为力！<BR><BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;先谢了！
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回复者：David Wong 回复日期：2002-10-01 22:18:19
<br>内容：MFC的桌面应用的基本编程框架是由应用、文档、视图、框架（对象）和模板五部分组成。<BR>对于初学者有一定的方便，但随着开发者的深入却有一定的限制。<BR>依照上述框架，文档可以对应一个或多个视图，但视图只能对应一个文档。<BR><BR>解决的一般方法是将文件的I/O功能做在一个或多个模块里，然后重载文档的<BR>OnOpenDocument和OnSaveDocument函数，在其中使用一个filter<BR>去判定文件扩展名，并调用相应的I/O操作。<BR><BR>BOOL CXXXDoc::OnOpenDocument(LPCTSTR lpszPathName) <BR>{<BR>&nbsp;&nbsp;&nbsp;&nbsp;CString filename(lpszPathName);<BR>&nbsp;&nbsp;&nbsp;&nbsp;CString ext(FindExtension(filename));<BR>&nbsp;&nbsp;&nbsp;&nbsp;ext.MakeLower();<BR>&nbsp;&nbsp;&nbsp;&nbsp;if (ext == "") return FALSE;<BR><BR>&nbsp;&nbsp;&nbsp;&nbsp;int type = 0;<BR>&nbsp;&nbsp;&nbsp;&nbsp;if (ext == "bmp")<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;......;&nbsp;&nbsp;&nbsp;&nbsp;<BR>&nbsp;&nbsp;&nbsp;&nbsp;else if (ext=="jpg" || ext=="jpeg")<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;......;&nbsp;&nbsp;&nbsp;&nbsp;<BR>&nbsp;&nbsp;&nbsp;&nbsp;else return FALSE;<BR><BR>&nbsp;&nbsp;&nbsp;&nbsp;...<BR><BR>&nbsp;&nbsp;&nbsp;&nbsp;return TRUE;<BR>}<BR><BR>BOOL CXXXDoc::OnSaveDocument(LPCTSTR lpszPathName) <BR>{<BR>&nbsp;&nbsp;&nbsp;&nbsp;CString filename(lpszPathName);<BR>&nbsp;&nbsp;&nbsp;&nbsp;CString ext(FindExtension(filename));<BR>&nbsp;&nbsp;&nbsp;&nbsp;ext.MakeLower();<BR>&nbsp;&nbsp;&nbsp;&nbsp;if (ext == "") return FALSE;<BR><BR>&nbsp;&nbsp;&nbsp;&nbsp;int type = 0;<BR>&nbsp;&nbsp;&nbsp;&nbsp;if (ext == "bmp")<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;......;&nbsp;&nbsp;&nbsp;&nbsp;<BR>&nbsp;&nbsp;&nbsp;&nbsp;else if (ext=="jpg" || ext=="jpeg")<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;......;&nbsp;&nbsp;&nbsp;&nbsp;<BR>&nbsp;&nbsp;&nbsp;&nbsp;else return FALSE;<BR><BR>&nbsp;&nbsp;&nbsp;&nbsp;...<BR><BR>&nbsp;&nbsp;&nbsp;&nbsp;return TRUE;<BR>}<BR><BR>你可以看一下MFC的source: docmgr.cpp和doccore.cpp。<BR>了解一下MFC文档、视图、框架（对象）和应用对象的关系。<BR>:)<BR><BR>
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<font color=red>答案被接受</font><br>回复者：David Wong 回复日期：2002-10-01 22:20:14
<br>内容：大家何谈请教，相互交流，相互鼓励，共同进步！<BR>好不好呀！？
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