Called by the framework before a document is printed or previewed.
The default implementation does nothing.
You must override this function to enable printing and print preview. Call the DoPreparePrinting member function, passing it the pInfo parameter, and then return its return value; DoPreparePrinting displays the Print dialog box and creates a printer device context. If you want to initialize the Print dialog box with values other than the defaults, assign values to the members of pInfo. For example, if you know the length of the document, pass the value to the SetMaxPage member function of pInfo before calling DoPreparePrinting. This value is displayed in the To: box in the Range portion of the Print dialog box.
DoPreparePrinting does not display the Print dialog box for a preview job. If you want to bypass the Print dialog box for a print job, check that the m_bPreview member of pInfo is FALSE and then set it to TRUE before passing it to DoPreparePrinting; reset it to FALSE afterwards.
If you need to perform initializations that require access to the CDC object representing the printer device context (for example, if you need to know the page size before specifying the length of the document), override the OnBeginPrinting member function.
If you want to set the value of the m_nNumPreviewPages or m_strPageDesc members of the pInfo parameter, do so after calling DoPreparePrinting. The DoPreparePrinting member function sets m_nNumPreviewPages to the value found in the application's .INI file and sets m_strPageDesc to its default value.
Override OnPreparePrinting and call DoPreparePrinting from the override so that the framework will display a Print dialog box and create a printer DC for you.
If you know how many pages the document contains, set the maximum page in OnPreparePrinting before calling DoPreparePrinting. The framework will display the maximum page number in the "to" box of the Print dialog box.