当用户切换控件栏的显示/隐藏时， FormView 应用程序的自动调整大小

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引言

我创建了一个 SDI 应用程序，并将所有控件放在视图中，使其派生自 CFormView。该应用程序还具有几个控制栏，如状态栏和几个可停靠的工具栏。当应用程序启动时，我将视图和父框架调整大小以使其紧密贴合我的控件。但是，当用户切换我的工具栏或状态栏的显示与隐藏时，框架窗口的大小，要么太大要么太小，无法显示视图。我所有调整应用程序大小的辛勤工作都白费了。所以我添加了一些代码，以便我的 CMainFrame 类可以在用户切换控制栏的显示与隐藏以适应视图时调整自身大小。虽然不是很复杂，但花了我一些时间来弄清楚如何最有效地做到这一点。

详细说明

以下是创建具有自动调整大小的 CMainFrame 类的步骤。另请参阅随附的源代码，以获取完整的演示应用程序和更多解释。

1. 创建一个单文档应用程序，其视图派生自 CFormView。
2. 使用类向导，为 MainFrame 添加消息处理程序，用于名为 RecalcLayout 的消息。
3. 在 CMainFrame 类中添加名为 m_nControlBarsWidth 和 m_nControlBarsHeight 的 private int 成员，并在构造函数中将它们初始化为 0。
4. 在 CMainFrame 类中添加名为 m_bCtrlBarsChanged 的 private bool 成员，并在构造函数中将其初始化为 false。
5. 将 CMainFrame::RecalcLayout 的实现更改为以下内容

   void CMainFrame::RecalcLayout(BOOL bNotify) 
   {
       // RecalcLayout is called by MFC when the frame window is resized. 
       // In this implementation of RecalcLayout, the application  
       // call SetWindowPos, which will resize the frame window.
       // Therefore, if RecalcLayout is called because 
       // the application is resizing the frame we want to ignore that call.
       // We use m_bCtrlBarsChanged to keep track if the application are  
       // resizing the frame window because the user toggled the controlbars  
       // on or off or if the user is resizing the window.
   
       if (m_bCtrlBarsChanged)
       { 
           // Ignore call since it's triggered by our call to SetWindowPos. 
           // Otherwise we will end up looping.
   
           return;
       }
   
       if (!IsIconic() && !IsZoomed())
       {
           // Calculate size of controlbars (statusbar and toolbars).  
           // We should only do this when the window is not maximized 
           // or minimized. When maximized we should not change
           // the window's size, it should stay maximized. I don't think this 
           // function can be called when window is minimized,
           // but if so then window size
           // should not be changed either.
   
           int nControlBarsHeightCurrent = 0;
           int nControlBarsWidthCurrent = 0;
   
           // Calculate the current total height and width of our controlbars.
           // We only care of a controlbar's height or width
           // depending on how it is docked.
   
           // We will use CWnd::RepositionBars() with
           // the reposQuery parameter to get 
           // measurements of our controlbars. 
   
           // A statusbar is always docked to bottom so only
           // height of statusbar is interesting.
   
           CRect rectControlBar;
   
           RepositionBars(AFX_IDW_STATUS_BAR, AFX_IDW_STATUS_BAR, 
              AFX_IDW_PANE_FIRST, reposQuery, &rectControlBar, NULL, FALSE);
           nControlBarsHeightCurrent += rectControlBar.Height();
   
           // Toolbars can be docked to any side of the frame so
           // depending on if a toolbar is added to the top or bottom
           // or if docked to left or right side, we need to 
           // add check its height or width.
   
           RepositionBars(AFX_IDW_DOCKBAR_TOP, AFX_IDW_DOCKBAR_TOP, 
              AFX_IDW_PANE_FIRST, reposQuery, &rectControlBar, NULL, FALSE);
           nControlBarsHeightCurrent += rectControlBar.Height();
   
           RepositionBars(AFX_IDW_DOCKBAR_BOTTOM, AFX_IDW_DOCKBAR_BOTTOM, 
              AFX_IDW_PANE_FIRST, reposQuery, &rectControlBar, NULL, FALSE);
           nControlBarsHeightCurrent += rectControlBar.Height();
   
           RepositionBars(AFX_IDW_DOCKBAR_LEFT, AFX_IDW_DOCKBAR_LEFT, 
              AFX_IDW_PANE_FIRST, reposQuery, &rectControlBar, NULL, FALSE);
           nControlBarsWidthCurrent += rectControlBar.Width();
   
           RepositionBars(AFX_IDW_DOCKBAR_RIGHT, AFX_IDW_DOCKBAR_RIGHT, 
              AFX_IDW_PANE_FIRST, reposQuery, &rectControlBar, NULL, FALSE);
           nControlBarsWidthCurrent += rectControlBar.Width(); 
   
           if (nControlBarsHeightCurrent != m_nControlBarsHeight || 
               nControlBarsWidthCurrent != m_nControlBarsWidth)
           {
               // The size of the controlbars have changed.
               // Lets resize the frame window 
               // to accommodate this change. The goal is to keep
               // the client window unchanged
               // and resize the frame instead.
   
               // Set m_bCtrlBarsChanged to true so we know
               // the application is resizing the 
               // dialog, not the user.
   
               m_bCtrlBarsChanged = true;
   
               // nControlBarsWidthCurrent - m_nControlBarsWidth
               // is how much the bars have 
               // changed in width and that is how much
               // the frame's width should be adjusted.
               // The calculations for height is similar.
   
               // Get the current size of the frame window.
   
               CRect rectFrame;
               GetWindowRect(rectFrame);
   
               // Adjust the size of the frame window. 
   
               SetWindowPos(NULL, 0, 0, 
                 rectFrame.Width() + 
                 nControlBarsWidthCurrent - m_nControlBarsWidth, 
                 rectFrame.Height() + 
                 nControlBarsHeightCurrent - m_nControlBarsHeight,
                 SWP_NOMOVE | SWP_NOZORDER | SWP_NOACTIVATE);
   
               // Save the size of the controlbars for next time
               // the user toggles the controlbars 
               // on or off so we know how much we should
               // adjust the size of the frame.
   
               m_nControlBarsWidth = nControlBarsWidthCurrent;
               m_nControlBarsHeight = nControlBarsHeightCurrent;
   
               // The application is finished resizing the dialog.
   
               m_bCtrlBarsChanged = false;
           }
       }
   
       CFrameWnd::RecalcLayout(bNotify);
   }

注释

CWnd::RepositionBars() 用于计算不同栏的 width 和 height。它需要根据我们的控制栏的停靠方式进行不同的调用。

如果您想添加对 CMainFrame::OnGetMinMaxInfo（WM_GETMINMAXINFO 的消息处理程序）的支持，则需要做一些额外的编码，因为当用户切换控制栏的显示与隐藏时，最小大小也必须更新。请参阅源代码以了解如何实现这一点。

文章历史

原始文章发布于 2002 年 1 月 28 日。此更新用于修复窗口最大化时的错误并处理多个工具栏。此外，之前未处理侧面停靠。我添加了另一张图片以更好地展示代码的运行情况。