In a report, regardless of the type or content of the various sections, there are three events for each section: Format, BeforePrint and AfterPrint.
Because there are many possible report designs, the event-raising sequence is dynamic in order to accommodate individual report demands. The only guaranteed sequence is that a section's Format event is raised before the BeforePrint event, which in turn occurs before the AfterPrint event but not necessarily all together. Reports should not be designed to rely on these events being raised in immediate succession.
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Important: Never reference the report's Fields collection in these section events. Only reference the Fields collection in the DataInitialize and FetchData events. |
Format event
ActiveReports raises this event after the data is loaded and bound to the controls contained in a section, but before the section is rendered to a page.
The Format event is the only event in which you can change the section's height. Use this section to set or change the properties of any controls or the section itself.
Also use the Format event to pass information, such as an SQL String, to a Subreport.
If the CanGrow or CanShrink property is True for the section or any control within the section, all of the growing and shrinking takes place in the Format event. Because of this, you cannot obtain information about a control or section's height in this event.
Because a section's height is unknown until the Format event finishes, it is possible for a section's Format event to be raised while the report is on a page to which the section is not rendered. For example, the Detail Format event is raised but the section is too large to fit on the page. This causes the PageFooter events and the PageEnd event to be raised on the current page, and the PageStart, any other Header events, and possibly the FetchData event to be raised before the section is rendered to the canvas on the next page.
BeforePrint event
ActiveReports raises this event before the section is rendered to the page.
The growing and shrinking of the section and its controls have already taken place. Therefore, you can use this event to get an accurate height of the section and its controls. You can modify values and resize controls in the BeforePrint event, but you cannot modify the height of the section itself.
Also use this event to do page-specific formatting since the report knows which page the section will be rendered to when this event is raised. Once this event has finished, the section cannot be changed in any way because the section is rendered to the canvas immediately after this event.
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Note: If a section contains the SubReport control that occupies more than one page, the SubReport gets split into smaller parts at rendering. In this case, you can use the BeforePrint event - it will fire multiple times to get the height of each part of the rendered SubReport. |
AfterPrint event
ActiveReports raises this event after the section is rendered to the page.
Although AfterPrint was an important event prior to ActiveReports Version 1 Service Pack 3, it is rarely used in any of the newer builds of ActiveReports. This event is still useful, however, if you want to draw on the page after text has already been rendered to it.