CBasePropertyPage.OnActivate method
[The feature associated with this page, DirectShow, is a legacy feature. It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation. Those features have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer, IMFMediaEngine and Audio/Video Capture in Media Foundation instead of DirectShow, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]
The OnActivate method is called when the property page is activated.
Syntax
virtual HRESULT OnActivate();
Parameters
This method has no parameters.
Return value
The base-class implementation returns S_OK.
Remarks
The CBasePropertyPage::Activate method calls the OnActivate method. In your derived class, override OnActivate to initialize the dialog box.
Examples
The following example initializes a trackbar control. This example assumes that m_pOwningFilter is a pointer to a custom interface on the filter associated with the property page. (Use the CBasePropertyPage::OnConnect method to initialize such pointers.)
HRESULT CMyProp::OnActivate(void)
{
ASSERT(m_pOwningFilter != NULL);
m_pOwningFilter->GetSomeProperty(&m_lOldVal);
SendDlgItemMessage(m_Dlg, IDC_SLIDER1, TBM_SETRANGE, 0, MAKELONG(0, 100));
SendDlgItemMessage(m_Dlg, IDC_SLIDER1, TBM_SETTICFREQ, 10, 0);
SendDlgItemMessage(m_Dlg, IDC_SLIDER1, TBM_SETPOS, 1, m_lOldVal);
return S_OK;
}
Requirements
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