我正在编写一个简单的绘画应用程序,并且在状态栏中添加了坐标显示。我只希望在有打开的文档时显示它。当我启动程序时,它显示空闲消息Ready
。
我将使用什么功能来测试打开的文档?
这是我的OnMouseMove()
处理程序:
void CMDIView::OnMouseMove(UINT nFlags, CPoint point)
{
// Define a Device Context object for the view
CClientDC aDC(this); // DC is for this view
// Verify the left button is down and mouse messages captured
if((nFlags & MK_LBUTTON) && (this == GetCapture()))
{
m_SecondPoint = point; // Save the current cursor position
if(m_pTempElement)
{
// An element was created previously
if(ElementType::CURVE == GetDocument()->GetElementType()) // A curve?
{ // We are drawing a curve so add a segment to the existing curve
std::static_pointer_cast<CCurve>(m_pTempElement)->AddSegment(m_SecondPoint);
m_pTempElement->Draw(&aDC); // Now draw it
return; // We are done
}
else
{
// If we get to here it's not a curve so
// redraw the old element so it disappears from the view
aDC.SetROP2(R2_NOTXORPEN); // Set the drawing mode
m_pTempElement->Draw(&aDC); // Redraw the old element to erase it
}
}
// Create a temporary element of the type and color that
// is recorded in the document object, and draw it
m_pTempElement.reset(CreateElement()); // Create a new element
m_pTempElement->Draw(&aDC); // Draw the element
}
{ //Coordinates display
CString s;
s.Format(L"X=%d Y=%d", point.x, point.y);
CMainFrame* pFrame = (CMainFrame*)AfxGetApp()->m_pMainWnd;
CStatusBar* pStatus = &pFrame->m_wndStatusBar;
pStatus->SetPaneText(0, s);
}
}
固定:
CMDIDoc::~CMDIDoc()
{
CString Idle = LPCTSTR(AFX_IDS_IDLEMESSAGE);
//Idle = LPCTSTR(L"lawlawlwawl");
CMainFrame* pFrame = (CMainFrame*)AfxGetApp()->m_pMainWnd;
CStatusBar* pStatus = &pFrame->m_wndStatusBar;
pStatus->SetPaneText(0, Idle );
}
最佳答案
如果没有打开的文档,则调用MDIGetActive
应该返回NULL
。
但是,如果是这种情况,那么您也将没有任何视图,并且该视图是-我假设-您在问题中显示的CMDIView
类。
也许一种替代方法是从您的CMainFrame
实例而不是从视图中处理状态栏文本的显示。
因此,在您的CMainFrame
中(以伪代码),
if (MDIGetActive() == NULL)
// display "Ready"
else
// ask current view for the text
另一种选择是捕获
CDocument
的破坏,然后将状态栏文本重置为“就绪”。正如@Edward所指出的那样,让主机处理文本显示并根据当前视图是否存在和/或希望提供文本来决定是否设置文本本身,将是更安全和更好的封装。关于c++ - 测试打开的文档,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/20877317/