chap8_3.htm

非常好的应用vc＋＋6.0进行相关网络程序开发的教程

    <p>//}}AFX_MSG</p>
    <p>DECLARE_MESSAGE_MAP()</p>
    <p>};</p>
    <p></font><font SIZE="3">　</font><font FACE="Times New Roman" SIZE="3"></p>
    <p></font><font SIZE="3">这里我们使用 
    指针链表模板来保存指向每个笔划的指针：</font><font FACE="Times New Roman" SIZE="3"></p>
    <p>CTypedPtrList&lt;CObList,CStroke*&gt; m_strokeList; </p>
    <p></font><font SIZE="3">其中“</font><font FACE="Times New Roman" SIZE="3">&lt;&gt;</font><font SIZE="3">”第一个参数表示链表基本类型，第二个参数代表链表中所存放的元素的类型。</p>
    <p>为了使用模板，还要修改</font><font FACE="Times New Roman" SIZE="3">stdafx.h</font><font SIZE="3">，在其中加入</font><font FACE="Times New Roman" SIZE="3">afxtempl..h</font><font SIZE="3">头文件，它包含了使用模板时所需的类型定义和宏：</font><font FACE="Times New Roman" SIZE="3"></p>
    <p>//.........</p>
    <p>#define VC_EXTRALEAN // Exclude rarely-used stuff from Windows headers</p>
    <p>#include &lt;afxwin.h&gt; // MFC core and standard components</p>
    <p>#include &lt;afxext.h&gt; // MFC extensions</p>
    <p></font><b><font SIZE="3">　</font><font FACE="Times New Roman" SIZE="3"></p>
    <p>#include &lt;afxtempl.h&gt; // MFC templates</b></p>
    <p>#include &lt;afxdisp.h&gt; // MFC OLE automation classes</p>
    <p>#ifndef _AFX_NO_AFXCMN_SUPPORT</p>
    <p>#include &lt;afxcmn.h&gt; // MFC support for Windows Common Controls</p>
    <p>#endif // _AFX_NO_AFXCMN_SUPPORT</p>
    <p>//......</p>
    <p></font><font SIZE="3">由于绘图程序需要卷滚文档，因此象前面的编辑那样，增加一个</font><font FACE="Times New Roman" SIZE="3">m_sizeDoc</font><font SIZE="3">数据成员存放文档的大小。另外，还需要提供一个</font><font FACE="Times New Roman" SIZE="3">GetDocSize()</font><font SIZE="3">来访问它。</font><font FACE="Times New Roman" SIZE="3">NewStroke()</font><font SIZE="3">用于往链表里增加一个笔划。</font><font FACE="Times New Roman" SIZE="3"></p>
    <p></font><font SIZE="3">现在，开始设计</font><font FACE="Times New Roman" SIZE="3">CStroke</font><font SIZE="3">类。笔划可以看作由一系列点组成，这样</font><font FACE="Times New Roman" SIZE="3">CStroke</font><font SIZE="3">可以用一个点的数组来表示。另外，还需要一些成员函数来访问这个数组。我们还希望笔划能够自己绘制自己，并用串行化机制保存自己的数据。</font><font FACE="Times New Roman" SIZE="3"></p>
    <p>CStroke</font><font SIZE="3">类定义清单如</font><font FACE="Times New Roman" SIZE="3">8.4</font><font SIZE="3">，我们把它在</font><font FACE="Times New Roman" SIZE="3">CDrawDoc</font><font SIZE="3">类定义之前。<b></p>
    <p>清单</font><font FACE="Times New Roman" SIZE="3">8.4 CStroke</font><font SIZE="3">类定义</font></b><font FACE="Times New Roman" SIZE="3"></p>
    <p>class CStroke : public CObject</p>
    <p>{</p>
    <p>public:</p>
    <p>CStroke(UINT nPenWidth);//</font><font SIZE="3">用笔的宽度构造一个画笔</font><font FACE="Times New Roman" SIZE="3"></p>
    <p>//</font><font SIZE="3">用于串行化笔划对象</font><font FACE="Times New Roman" SIZE="3"></p>
    <p>protected:</p>
    <p>CStroke(); //</font><font SIZE="3">串行化对象所需的不带参数的构造函数</font><font FACE="Times New Roman" SIZE="3"></p>
    <p>DECLARE_SERIAL(CStroke)</p>
    <p>// Attributes</p>
    <p>protected:</p>
    <p>UINT m_nPenWidth; // one pen width applies to entire stroke</p>
    <p>public:</p>
    <p>//</font><font SIZE="3">用数组模板类保存笔划的所有点</font><font FACE="Times New Roman" SIZE="3"></p>
    <p>CArray&lt;CPoint,CPoint&gt; m_pointArray; // series of connected points</p>
    <p>//</font><font SIZE="3">包围笔划所有的点的一个最小矩形，关于它的作用以后会提到</font><font FACE="Times New Roman" SIZE="3"></p>
    <p>CRect m_rectBounding; // smallest rect that surrounds all</p>
    <p>// of the points in the stroke</p>
    <p>// measured in MM_LOENGLISH units</p>
    <p>// (0.01 inches, with Y-axis inverted)</p>
    <p>public:</p>
    <p>CRect&amp; GetBoundingRect() { return m_rectBounding; }</p>
    <p>//</font><font SIZE="3">结束笔划，计算最小矩形</font><font FACE="Times New Roman" SIZE="3"></p>
    <p>void FinishStroke();</p>
    <p>// Operations</p>
    <p>public:</p>
    <p>//</font><font SIZE="3">绘制笔划</font><font FACE="Times New Roman" SIZE="3"></p>
    <p>BOOL DrawStroke(CDC* pDC);</p>
    <p>public:</p>
    <p>virtual void Serialize(CArchive&amp; ar);</p>
    <p>};</font><font SIZE="3"><b></p>
    <p></b><font color="#3973DE">文档的初始化</font></font><font FACE="Times New Roman" SIZE="3"></p>
    <p></font><font SIZE="3">文档的初始化在</font><font FACE="Times New Roman" SIZE="3">OnNewDocument()</font><font SIZE="3">和</font><font FACE="Times New Roman" SIZE="3">OnOpenDocument()</font><font SIZE="3">中完成。对于</font><font FACE="Times New Roman" SIZE="3">Draw</font><font SIZE="3">程序来说，两者的初始化相同，因此设计一个</font><font FACE="Times New Roman" SIZE="3">InitDocument()</font><font SIZE="3">函数用于文档初始化：</font><b><font FACE="Times New Roman" SIZE="3"></p>
    <p>void CDrawDoc::InitDocument()</p>
    <p>{</p>
    <p>m_nPenWidth=2;</p>
    <p>m_nPenCur.CreatePen(PS_SOLID,m_nPenWidth,RGB(0,0,0));</p>
    <p>//</font><font SIZE="3">缺省文档大小设置为</font><font FACE="Times New Roman" SIZE="3">800X900</font><font SIZE="3">个逻辑单位</font><font FACE="Times New Roman" SIZE="3"></p>
    <p>m_sizeDoc = CSize(800,900);</p>
    <p>}</b></p>
    <p>InitDocument()</font><font SIZE="3">函数将笔的宽度初值设为</font><font FACE="Times New Roman" SIZE="3">2</font><font SIZE="3">，然后创建一个画笔对象。该对象在以后绘图是要用到。最后将文档尺寸大小设置为</font><font FACE="Times New Roman" SIZE="3">800X900</font><font SIZE="3">个逻辑单位。</font><font FACE="Times New Roman" SIZE="3"></p>
    <p></font><font SIZE="3">然后在</font><font FACE="Times New Roman" SIZE="3">OnNewDocument()</font><font SIZE="3">和</font><font FACE="Times New Roman" SIZE="3">OnOpenDocument()</font><font SIZE="3">中调用它：</font><font FACE="Times New Roman" SIZE="3"></p>
    <p>void CDrawDoc::OnNewDocument()</p>
    <p>{</p>
    <p>if (!CDocument::OnNewDocument())</p>
    <p>return FALSE;</p>
    <p>// TODO: add reinitialization code here</p>
    <p>// (SDI documents will reuse this document)</p>
    <p></font><b><font SIZE="3">　</font><font FACE="Times New Roman" SIZE="3"></p>
    <p>InitDocument();</b></p>
    <p>return TRUE;</p>
    <p>}</p>
    <p>AppWizard</font><font SIZE="3">并没有生成</font><font FACE="Times New Roman" SIZE="3">OnOpenDocument()</font><font SIZE="3">的代码，因此要用</font><font FACE="Times New Roman" SIZE="3">ClassWizard</font><font SIZE="3">来生成</font><font FACE="Times New Roman" SIZE="3">OnOpenDocument()</font><font SIZE="3">的框架。生成框架后，在其中加入代码：</font><font FACE="Times New Roman" SIZE="3"></p>
    <p>BOOL CDrawDoc::OnOpenDocument(LPCTSTR lpszPathName) </p>
    <p>{</p>
    <p>if (!CDocument::OnOpenDocument(lpszPathName))</p>
    <p>return FALSE;</p>
    <p></font><font SIZE="3">　</font><font FACE="Times New Roman" SIZE="3"></p>
    <p>// TODO: Add your specialized creation code here</p>
    <p></font><b><font SIZE="3">　</font><font FACE="Times New Roman" SIZE="3"></p>
    <p>InitDocument();</b></p>
    <p>return TRUE;</p>
    <p>}</font><font SIZE="3"><b></p>
    <p></b><font color="#3973DE">文档的清理</font></font><font FACE="Times New Roman" SIZE="3"></p>
    <p></font><font SIZE="3">在关闭文档的最后一个子窗口时，框架要求文档清理数据。文档清理在文档类的</font><font FACE="Times New Roman" SIZE="3">DeleteContents()</font><font SIZE="3">中完成。同样需要用</font><font FACE="Times New Roman" SIZE="3">ClassWizard</font><font SIZE="3">生成</font><font FACE="Times New Roman" SIZE="3">DeleteContents</font><font SIZE="3">的框架。</font><font FACE="Times New Roman" SIZE="3"></p>
    <p>void CDrawDoc::DeleteContents() </p>
    <p>{</p>
    <p>// TODO: Add your specialized code here and/or call the base class</p>
    <p></font><b><font SIZE="3">　</font><font FACE="Times New Roman" SIZE="3"></p>
    <p>while (!m_strokeList.IsEmpty())</p>
    <p>{</p>
    <p>delete m_strokeList.RemoveHead();</p>
    <p>}</b></p>
    <p>CDocument::DeleteContents();</p>
    <p>}</p>
    <p>DeleteContents()</font><font SIZE="3">从头到尾遍里链表中的所有对象指针，并通过指针删除对象，然后用</font><font FACE="Times New Roman" SIZE="3">RemoveHead()</font><font SIZE="3">删除该指针。<b></p>
    <p></b><font color="#3973DE">文档的串行化</font></font><font FACE="Times New Roman" SIZE="3"></p>
    <p></font><font SIZE="3">现在设计文档的</font><font FACE="Times New Roman" SIZE="3">Serialize</font><font SIZE="3">函数，实现文档数据的保存和载入：</font><font FACE="Times New Roman" SIZE="3"></p>
    <p>void CDrawDoc::Serialize(CArchive&amp; ar)</p>
    <p>{</p>
    <p>if (ar.IsStoring())</p>
    <p>{</p>
    <p></font><b><font SIZE="3">　</font><font FACE="Times New Roman" SIZE="3"></p>
    <p>ar &lt;&lt; m_sizeDoc;</b></p>
    <p>}</p>
    <p>else</p>
    <p>{</p>
    <p></font><b><font SIZE="3">　</font><font FACE="Times New Roman" SIZE="3"></p>
    <p>ar &gt;&gt; m_sizeDoc;</b></p>
    <p>}</p>
    <p></font><b><font SIZE="3">　</font><font FACE="Times New Roman" SIZE="3"></p>
    <p>m_strokeList.Serialize(ar);</b></p>
    <p>}</p>
    <p></font><font SIZE="3">文档的</font><font FACE="Times New Roman" SIZE="3">Serialize()</font><font SIZE="3">函数首先分别保存和载入文档大小，然后调用</font><font FACE="Times New Roman" SIZE="3">m_strokeList</font><font SIZE="3">的</font><font FACE="Times New Roman" SIZE="3">Serialize()</font><font SIZE="3">方法。</font><font FACE="Times New Roman" SIZE="3">m_strokeList.Serialize()</font><font SIZE="3">又会自动调用存放在</font><font FACE="Times New Roman" SIZE="3">m_strokeList</font><font SIZE="3">中的每一个元素</font><font FACE="Times New Roman" SIZE="3">CStroke</font><font SIZE="3">的串行化方法</font><font FACE="Times New Roman" SIZE="3">CStroke.Serialize()</font><font SIZE="3">最终实现文档的串行化即文档所包含的对象的存储和载入。</font><font FACE="Times New Roman" SIZE="3"></p>
    <p></font><font SIZE="3">在</font><font FACE="Times New Roman" SIZE="3">DrawDoc.cpp</font><font SIZE="3">的末尾加上</font><font FACE="Times New Roman" SIZE="3">CStroke::Serialize()</font><font SIZE="3">函数的定义：</font><font FACE="Times New Roman" SIZE="3"><b></p>
    <p>void CStroke::Serialize(CArchive&amp; ar)</p>
    <p>{</p>
    <p>if (ar.IsStoring())</p>
    <p>{</p>
    <p>ar &lt;&lt; m_rectBounding;</p>
    <p>ar &lt;&lt; (WORD)m_nPenWidth;</p>
    <p>m_pointArray.Serialize(ar);</p>
    <p>}</p>
    <p>else</p>
    <p>{</p>
    <p>ar &gt;&gt; m_rectBounding;</p>
    <p>WORD w;</p>
    <p>ar &gt;&gt; w;</p>
    <p>m_nPenWidth = w;</p>
    <p>m_pointArray.Serialize(ar);</p>
    <p>}</p>
    <p>}</b></p>
    <p>CStroke</font><font SIZE="3">的</font><font FACE="Times New Roman" SIZE="3">Serialize()</font><font SIZE="3">依次保存（载入）笔划的矩形边界、线宽度以及点数组。注意</font><font FACE="Times New Roman" SIZE="3">m_nPenWidth</font><font SIZE="3">是</font><font FACE="Times New Roman" SIZE="3">UINT</font><font SIZE="3">类型的，</font><font FACE="Times New Roman" SIZE="3">&gt;&gt;</font><font SIZE="3">和</font><font FACE="Times New Roman" SIZE="3">&lt;&lt;</font><font SIZE="3">操作符并不支持</font><font FACE="Times New Roman" SIZE="3">UINT</font><font SIZE="3">类型但却支持</font><font FACE="Times New Roman" SIZE="3">WORD</font><font SIZE="3">，因此要作</font><font FACE="Times New Roman" SIZE="3">UINT</font><font SIZE="3">和</font><font FACE="Times New Roman" SIZE="3">DWORD</font><font SIZE="3">之间的类型转换。点数组的串行化通过调用数组的每个</font><font FACE="Times New Roman" SIZE="3">CPoint</font><font SIZE="3">类元素的</font><font FACE="Times New Roman" SIZE="3">Serialize()</font><font SIZE="3">完成，</font><font FACE="Times New Roman" SIZE="3">CPoint</font><font SIZE="3">类是</font><font FACE="Times New Roman" SIZE="3">MFC</font><font SIZE="3">类，它本身支持串行化。</font><font FACE="Times New Roman"><b></p>
    <p></b></font><font color="#3973DE" FACE="Times New Roman">8.3.3 </font><font color="#3973DE">设计绘图程序的视图类</font></p>
    <p><font SIZE="3"><b>　</p>
    <p></b><font color="#3973DE">视图类数据成员</font></font><font FACE="Times New Roman" SIZE="3"></p>
    <p></font><font SIZE="3">现在着手设计绘图程序的视图类。首先，需要在视图中增加两个数据成员：</font><font FACE="Times New Roman" SIZE="3"></p>
    <p>class CDrawView : public CScrollView</p>
    <p>{</p>
    <p>protected: // create from serialization only</p>
    <p>CDrawView();</p>