如何在MFC中访问主对话框的元素？ 在视觉编辑器VS 2012中创建了Element

Question

I have created in VS 2012, in a visual resource editor, few components on the main form of the application (one of them is CStatic text).

I want now to access it, so I have wrote somewhere in my MainFrm.cpp (the code executes after clicking one of the buttons, so after everything was constructed):

CStatic * temp = (CStatic *) GetDlgItem(IDC_OPERATION_INFO);
temp->SetWindowText(text);

And while executing second line of the code, I get error:

Debug Assertion Failed!
Program: C:\Windows\system32\mfc110ud.dll
File: f:\\dd\vctools\vc7libs\ship\atlmfc\src\mfc\winocc.cpp
Line: 245

What I'm doing wrong?

The CStatic was created via visual editor, not in the code. Ofc I see it on the application.

Answer 1

The static control is probably on a CDialog or CFormView derived class, not CMainFrame. GetDlgItem only works for controls that are a child of the calling class.

A better way to access the control is to right click on it in the visual editor and select 'Add Variable'. It will let you add a CStatic variable (like m_opinfo) to the correct parent class. Then that class can call m_opinfo.SetWindowText(text).

Answer 2

You should also note that GetDlgItem can be unsafe to use since it returns a temporary pointer. The pointer is only valid for the scope of the code (method) that is executing. You should follow ScottMcP suggestion.