Controlling Map Refresh Operations - Autodesk 15606-011408-9330 - MAPGUIDE R6.3 SITE LIC-UPG R6 Developer's Manual

Controlling Map Refresh Operations

You can ensure that Autodesk MapGuide Viewer will not enter a busy state
by controlling when display refreshes occur. The first step is to remember
that display refreshes always occur in the following instances:
I When the autoRefresh flag is set to True with MGMap.setAutoRefresh,
and the application calls an API method that requires an automatic refresh
such as MGMap.zoomSelected. Methods requiring an automatic refresh
are noted in the Autodesk MapGuide Viewer API Help.
I Your application calls zoomGotoDlg, zoomGotoLocation, setUrl, or
refresh. These methods always invoke a display refresh, even if the
autoRefresh flag is set to false. The only exception is if you call one of
these methods from onViewChanging or onMapLoaded event handling
code. Under these circumstances, the methods will fail and will set error
code to -14 (refresh disabled) because the onViewChanging and
onMapLoaded events always disable the autoRefresh flag.
Using the autoRefresh Flag
To develop an application that executes smoothly, you need to prevent busy
states while the application calls methods in the API that do not work during
the busy state. To do this, you need to disable the autoRefresh flag.
To disable the autoRefresh Flag
1 Set the autoRefresh flag to False immediately before calling the first
method.
2 Reset the autoRefresh flag to True.
3 Call the refresh method immediately after your application calls the
other methods that do not work during the busy state. Simply setting the
autoRefresh flag back to True with MGMap.setAutoRefresh does not
refresh the map. For example:
function selectAndZoomToPointObject(mgObj)
{
var map = getMap();
var sel = map.getSelection();
map.setAutoRefresh(false); // Prevent busy state from happening
sel.clear();
sel.addObject(mgObj);
map.zoomSelected();
map.setWidth(5, "KM");
map.setAutoRefresh(true);
map.refresh();
}
// when zoomSelected is called
// Reset the autoRefresh flag
// Update the display
Handling Busy State and Map Refresh
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