ChartDirector 7.0 (ASP/COM/VB Edition)
Refreshes the <IMG> that the JsChartViewer is bound to.
, this method does not send the JsChartViewer state to the server. It merely sends a new request to the server using the existing URL of the <IMG> tag.
- Double buffering
- Overlapping updating
Due to the nature of Internet connections, it is sometimes hard to predict the response time for a chart update. For application that needs to update the chart frequently, it may be possible the a new request be sent before an existing request is completed.
In the streamUpdate method, new update requests will be ignored until existing requests are completed, or until a given timeout has occurred. This ensures the chart does get updated.
- Error handling
In the streamUpdate method, if the update request failed, nothing will happen, and the existing chart will still be shown. The system will simply wait for the next update request.
- Cache avoidance
To avoid caching by the browser and/or intermediate proxy servers, the streamUpdate method will append dummy unique query parameters to the <IMG> URL to ensure each URL is unique, and so avoids the cache.
|timeout||60||If there is already an existing update request in progress, the timeout value determines whether to abort the existing request and continue with the new request, or vice versa. If the existing request has been in progress for longer than the timeout value in seconds, it will be aborted, otherwise the new request will be aborted.|
|extraQuery||""||Extra query parameters that can be sent with the request. An example is "a=b&c=d".
True if a new streamUpdate request is sent out. False if the new streamUpdate request is aborted (due to an outstanding request).
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