📄 visual c++编程技巧之八.htm

📁 载之“阿蒙编程乐园”
💻 HTM
📖 第 1 页 / 共 2 页
字号:
12 下一页
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<!-- saved from url=(0038)http://www.vchome.net/tech/vctip8.html -->
<HTML><HEAD><TITLE>Visual C++编程技巧之八</TITLE>
<META http-equiv=Content-Type content="text/html; charset=gb2312">
<META content="MSHTML 5.50.4134.100" name=GENERATOR>
<META content=sss name=doccomm>
<META content=C:\MSOffice\Template\Sl_BOOK.dot name=Template>
<META content="Cheng Jinxing" name=Author></HEAD>
<BODY text=#000000 vLink=#551a8b aLink=#ff0000 link=#0000ee bgColor=#ccffff>
<P align=center><BR><FONT face=楷体_GB2312 size=+3>Visual C++编程技巧之八</FONT> &nbsp; 
</P>
<P><A href="http://www.vchome.net/tech/vctip8.html#tip57"><FONT 
face="Times New Roman" size=+0>57</FONT><FONT size=+0>、为什么即使调用</FONT><FONT 
face="Times New Roman" size=+0>EnableMenuItem</FONT><FONT 
size=+0>菜单项后，菜单项还处于禁止状态</FONT></A> </P>
<P><A href="http://www.vchome.net/tech/vctip8.html#tip58"><FONT 
face="Times New Roman" size=+0>58</FONT><FONT size=+0>、如何给系统菜单添加一个菜单项</FONT></A> 
</P>
<P><A href="http://www.vchome.net/tech/vctip8.html#tip59"><FONT 
face="Times New Roman" size=+0>59</FONT><FONT 
size=+0>、如何确定顶层菜单所占据的菜单行数</FONT></A> </P>
<P><A href="http://www.vchome.net/tech/vctip8.html#tip60"><FONT 
face="Times New Roman" size=+0>60</FONT><FONT 
size=+0>、在用户环境中如何确定系统显示元素的颜色</FONT></A> </P>
<P><A href="http://www.vchome.net/tech/vctip8.html#tip61"><FONT 
face="Times New Roman" size=+0>61</FONT><FONT size=+0>、如何查询和设置系统参数</FONT></A> 
</P>
<P><A href="http://www.vchome.net/tech/vctip8.html#tip62"><FONT 
face="Times New Roman" size=+0>62</FONT><FONT size=+0>、如何使用一个预定义的</FONT><FONT 
face="Times New Roman" size=+0>Windows</FONT><FONT size=+0>光标</FONT></A> </P>
<P><A href="http://www.vchome.net/tech/vctip8.html#tip63"><FONT 
face="Times New Roman" size=+0>63</FONT><FONT size=+0>、如何确定当前屏幕分辨率</FONT></A> 
</P>
<P><A href="http://www.vchome.net/tech/vctip8.html#tip64"><FONT 
face="Times New Roman" size=+0>64</FONT><FONT size=+0>、如何检索原先的</FONT><FONT 
face="Times New Roman" size=+0>Task Manager</FONT><FONT 
size=+0>应用程序使用的任务列表</FONT></A> </P>
<P><A href="http://www.vchome.net/tech/vctip8.html#tip65"><FONT 
face="Times New Roman" size=+0>65</FONT><FONT size=+0>、如何确定</FONT><FONT 
face="Times New Roman" size=+0>Windows</FONT><FONT size=+0>和</FONT><FONT 
face="Times New Roman" size=+0>Windows</FONT><FONT size=+0>系统目录</FONT></A> </P>
<P><A href="http://www.vchome.net/tech/vctip8.html#tip66"><FONT 
face="Times New Roman" size=+0>66</FONT><FONT size=+0>、在哪儿创建临文件</FONT></A> </P>
<P><A href="http://www.vchome.net/tech/vctip8.html#tip67"><FONT 
face="Times New Roman" size=+0>67</FONT><FONT size=+0>、如何访问桌面窗口</FONT></A> </P>
<P><FONT size=+2><B>　</B></FONT> </P>
<P><A name=tip57></A><B><FONT size=+2><FONT 
face="Times New Roman">57</FONT><FONT face=黑体>、为什么即使调用</FONT><FONT 
face="Times New Roman">EnableMenuItem</FONT><FONT 
face=黑体>菜单项后，菜单项还处于禁止状态</FONT></FONT></B> </P>
<P><FONT size=+0>需要将<FONT face="Times New Roman">CFrameWnd:: 
m_bAutomenuEnable</FONT>设置为<FONT 
face="Times New Roman">FALSE</FONT>，如果该数据成员为<FONT 
face="Times New Roman">TRUE</FONT>（缺省值），工作框将自动地禁止没有<FONT 
face="Times New Roman">ON_UPDATE_COMMAND_UI</FONT>或者<FONT 
face="Times New Roman">ON_COMMAND</FONT>的菜单项。</FONT> </P>
<P><FONT face="Times New Roman" size=+0>//Disable MFC from automatically 
disabling menu items.</FONT> </P>
<P><FONT face="Times New Roman" size=+0>m_bAuoMenuEnable=FALSE;</FONT> </P>
<P><FONT face="Times New Roman" size=+0>//Now enable the menu item.</FONT> </P>
<P><FONT face="Times New Roman" size=+0>CMenu* pMenu=GetMenu ();</FONT> </P>
<P><FONT face="Times New Roman" size=+0>ASSERT_VALID (pMenu);</FONT> </P>
<P><FONT face="Times New Roman" size=+0>pMenu-&gt;EnableMenuItem 
(ID_MENU_ITEM,MF_BYCOMMAND | MF_ENABLED);</FONT> </P>
<P><A name=tip58></A><B><FONT size=+2><FONT 
face="Times New Roman">58</FONT><FONT face=黑体>、如何给系统菜单添加一个菜单项</FONT></FONT></B> 
</P>
<P><FONT size=+0>给系统菜单添加一个菜单项需要进行下述三个步骤：</FONT> </P>
<P><FONT size=+0>首先，使用<FONT face="Times New Roman">Resource 
Symbols</FONT>对话（在<FONT face="Times New Roman">View</FONT>菜单中选择<FONT 
face="Times New Roman">Resource Symbols</FONT>．．．</FONT> </P>
<P><FONT size=+0>可以显示该对话）定义菜单项<FONT face="Times New Roman">ID</FONT>，该<FONT 
face="Times New Roman">ID</FONT>应大于<FONT 
face="Times New Roman">0x0F</FONT>而小于<FONT 
face="Times New Roman">0xF000</FONT>；</FONT> </P>
<P><FONT size=+0>其次，调用<FONT 
face="Times New Roman">CWnd::GetSystemMenu</FONT>获取系统菜单的指针并调用<FONT 
face="Times New Roman">CWnd:: 
Appendmenu</FONT>将菜单项添加到菜单中。下例给系统菜单添加两个新的菜单项：</FONT> </P>
<P><FONT face="Times New Roman" size=+0>int CMainFrame:: OnCreate 
(LPCREATESTRUCT lpCreateStruct)</FONT> </P>
<P><FONT face="Times New Roman" size=+0>{</FONT> </P>
<P><FONT size=+0>…</FONT> </P>
<P><FONT face="Times New Roman" size=+0>//Make sure system menu item is in the 
right range.</FONT> </P>
<P><FONT face="Times New Roman" size=+0>ASSERT (IDM_MYSYSITEM 
&amp;0xFFF0)==IDM_MYSYSITEM);</FONT> </P>
<P><FONT face="Times New Roman" size=+0>ASSERT (IDM-MYSYSITEM&lt;0xF000);</FONT> 
</P>
<P><FONT face="Times New Roman" size=+0>//Get pointer to system menu.</FONT> 
</P>
<P><FONT face="Times New Roman" size=+0>CMenu* pSysmenu=GetSystemmenu 
(FALSE);</FONT> </P>
<P><FONT face="Times New Roman" size=+0>ASSERT_VALID (pSysMenu);</FONT> </P>
<P><FONT face="Times New Roman" size=+0>//Add a separator and our menu item to 
system menu.</FONT> </P>
<P><FONT face="Times New Roman" size=+0>CString StrMenuItem (_T ("New menu 
item"));</FONT> </P>
<P><FONT face="Times New Roman" size=+0>pSysMenu-&gt;Appendmenu 
(MF_SEPARATOR);</FONT> </P>
<P><FONT face="Times New Roman" size=+0>pSysMenu-&gt;AppendMenu (MF_STRING, 
IDM_MYSYSITEM, strMenuitem);</FONT> </P>
<P><FONT size=+0>…</FONT> </P>
<P><FONT face="Times New Roman" size=+0>}</FONT> </P>
<P><FONT size=+0>现在，选择系统菜单项时用户应进行检测。使用<FONT 
face="Times New Roman">ClassWizard</FONT>处理</FONT> </P>
<P><FONT size=+0><FONT 
face="Times New Roman">WM_SYSCOMMAND</FONT>消息并检测用户菜单的<FONT 
face="Times New Roman">nID</FONT>参数：</FONT> </P>
<P><FONT face="Times New Roman" size=+0>void CMainFrame:: OnSysCommand (UINT 
nID,LPARAM lParam)</FONT> </P>
<P><FONT face="Times New Roman" size=+0>{</FONT> </P>
<P><FONT face="Times New Roman" size=+0>//Determine if our system menu item was 
selected.</FONT> </P>
<P><FONT face="Times New Roman" size=+0>if ( (nID &amp; 
0xFFF0)==IDM_MYSYSITEM)</FONT> </P>
<P><FONT face="Times New Roman" size=+0>{</FONT> </P>
<P><FONT face="Times New Roman" size=+0>//TODO-process system menu item</FONT> 
</P>
<P><FONT face="Times New Roman" size=+0>}</FONT> </P>
<P><FONT face="Times New Roman" size=+0>else</FONT> </P>
<P><FONT face="Times New Roman" size=+0>CMDIFrameWnd:: OnSysCommand (nID, 
lParam);</FONT> </P>
<P><FONT face="Times New Roman" size=+0>}</FONT> </P>
<P><FONT size=+0>最后，一个设计良好的<FONT 
face="Times New Roman">UI</FONT>应用程序应当在系统菜单项加亮时在状态条显示一个帮助信息，这可以通过增加一个包含系统菜单基<FONT 
face="Times New Roman">ID</FONT>的串表的入口来实现。</FONT> </P>
<P><A name=tip59></A><B><FONT size=+2><FONT 
face="Times New Roman">59</FONT><FONT 
face=黑体>、如何确定顶层菜单所占据的菜单行数</FONT></FONT></B> </P>
<P><FONT 
size=+0>这可以通过简单的减法和除法来实现。首先，用户需要计算主框窗口的高度和客户区；其次，从主框窗口的高度中减去客户区、框边界以及标题的高度；最后，除以菜单栏的高度。下例成员函数是一个计算主框菜单所占据的行数的代码实现。</FONT> 
</P>
<P><FONT face="Times New Roman" size=+0>int CMainFrame:: GetMenuRows ()</FONT> 
</P>
<P><FONT face="Times New Roman" size=+0>{</FONT> </P>
<P><FONT face="Times New Roman" size=+0>CRect rcFrame,rcClient;</FONT> </P>
<P><FONT face="Times New Roman" size=+0>GetWindowRect (rcFrame);</FONT> </P>
<P><FONT face="Times New Roman" size=+0>GetClientRect (rcClient);</FONT> </P>
<P><FONT face="Times New Roman" size=+0>return (rcFrame.Height () 
-rcClient.Height ()-</FONT> </P>
<P><FONT face="Times New Roman" size=+0>:: GetSystemMetrics (SM_CYCAPTION) 
-</FONT> </P>
<P><FONT face="Times New Roman" size=+0>(:: getSystemMetrics (SM_CYFRAME) *2)) 
/</FONT> </P>
<P><FONT face="Times New Roman" size=+0>:: GetSystemMetrics (SM_CYMENU);</FONT> 
</P>
<P><FONT face="Times New Roman" size=+0>}</FONT> </P>
<P><A name=tip60></A><B><FONT size=+2><FONT 
face="Times New Roman">60</FONT><FONT 
face=黑体>、在用户环境中如何确定系统显示元素的颜色</FONT></FONT></B> </P>
<P><FONT size=+0>调用<FONT face="Times New Roman">SDK</FONT>函数<FONT 
face="Times New Roman">GetSysColor</FONT>可以获取一个特定显示元素的颜色。下例说明了如何在<FONT 
face="Times New Roman">MFC</FONT>函数<FONT face="Times New Roman">CMainFrameWnd:: 
OnNcPaint</FONT>中调用该函数设置窗口标题颜色。</FONT> </P>
<P><FONT face="Times New Roman" size=+0>void CMiniFrameWnd:: OnNcPaint ()</FONT> 
</P>
<P><FONT face="Times New Roman" size=+0>{</FONT> </P>
<P><FONT size=+0>…</FONT> </P>
<P><FONT face="Times New Roman" size=+0>dc.SetTextColor (:: GetSysColor 
(m_bActive ?</FONT> </P>
<P><FONT face="Times New Roman" size=+0>COLOR_CAPTIONTEXT : 
COLOR_INACTIVECAPTIONTEXT));</FONT> </P>
<P><FONT size=+0>…</FONT> </P>
<P><FONT face="Times New Roman" size=+0>}</FONT> </P>
<P><A name=tip61></A><B><FONT size=+2><FONT 
face="Times New Roman">61</FONT><FONT face=黑体>、如何查询和设置系统参数</FONT></FONT></B> 
</P>
<P><FONT size=+0>在<FONT face="Times New Roman">Windows 3.1 SDK</FONT>中介绍过<FONT 
face="Times New Roman">SDK</FONT>函数<FONT 
face="Times New Roman">SystemParametersInfo</FONT>，调用该函数可以查询和设置系统参数，诸如按键的重复速率设置、鼠标双击延迟时间、图标字体以及桌面覆盖位图等等。</FONT> 
</P>
<P><FONT face="Times New Roman" size=+0>//Create a font that is used for icon 
titles.</FONT> </P>
<P><FONT face="Times New Roman" size=+0>LOGFONT stFont;</FONT> </P>
<P><FONT face="Times New Roman" size=+0>:: SystemParametersInfo 
(SPIF_GETICONTITLELOGFONT,</FONT> </P>
<P><FONT face="Times New Roman" size=+0>sizeof (LOGFONT), &amp;stFont, 
SPIF_SENDWININICHANGE);</FONT> </P>
<P><FONT face="Times New Roman" size=+0>m_font.CreateFontIndirect 
(&amp;stFont);</FONT> </P>
<P><FONT face="Times New Roman" size=+0>//Change the wallpaper to 
leaves.bmp.</FONT> </P>
<P><FONT face="Times New Roman" size=+0>:: SystemParametersInfo 
(SPI_SETDESKWALLPAPER, 0,</FONT> </P>
12 下一页
💿 文件大小 40 K
👤 上传用户 taiyubao
📂 所属分类文章/文档
🏷️ 相关标签

#编程
⌨️ 快捷键说明

复制代码 Ctrl + C
搜索代码 Ctrl + F
全屏模式 F11
切换主题 Ctrl + Shift + D
显示快捷键 ?
增大字号 Ctrl + =
减小字号 Ctrl + -