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| Author | Forum: PowerWEB LiveControls for ASP.NET Topic: long delays on callback |
| bseibenick From: Toledo, OH USA Posts: 22 Member Since: 05/16/05 |
posted February 8, 2006 1:49 PM I have been trying to figure out an issue with long delays in waiting for a response from callbacks. What I am doing is selecting a company name from a live dropdown and then in the codebehind i am setting a live label equal to the address info for the company. When my company dropdown has ~100 companies in it the label gets populated in less than a second. When my company dropdown has the full 5500 companies it takes almost 10 seconds to populate the label. I have already turned off the viewstate on every control on the page except the company dropdown. When I try disable the viewstate on the live dropdown the callback does not function. Any ideas on how to handle live controls with large amounts of data in them? Thanks, Brian |
John Talarico From: Rome, NY USA Posts: 630 Member Since: 06/01/05 |
posted February 8, 2006 2:23 PM I'm not sure what the delay may be coming from, but in a simple test I was able to populate a LiveDropDownList with 10000 items and in the SelectedIndexChanged event I set a LiveLabel.Text = LiveDropDownList.SelectedValue. I see no delay at all. Are you populating the LiveDropDownList in the Page_Load event? |
| bseibenick From: Toledo, OH USA Posts: 22 Member Since: 05/16/05 |
posted February 8, 2006 2:40 PM Yes, I am populating the dropdown from a sql database using the page_load event. I am using the following code to prevent the dropdown from loading multiple times... sub page_load... if not Page.IsPostBack then 'load dropdown data from sql db (sub routine initializes dropdown...) end if end sub |
| John Talarico From: Rome, NY USA Posts: 630 Member Since: 06/01/05 |
posted February 8, 2006 2:54 PM Something else must be causing the delay then, because my test does the same thing. If you step through the code, is there a single point where you can see the delay occur? I have sent you my sample webform to compare to your application. |
| jowi From: The Hague, Netherlands Posts: 3 Member Since: 03/15/06 |
posted March 15, 2006 8:09 AM I'm looking for an AJAX solution, and tested with LiveControls. I experience the same problem here. Up to 1000 items is ok, no noticable delay, but when populating the control with 1000+ items, it takes a few seconds to complete the load. With 10000+ items, it takes almost minutes, while the form is unaccessible. Testing the same code with the 'normal' controls, they populate instantly, no delay. This way, using old controls and re-loading the page is even faster than using the LiveControls... What could be wrong? |
| John Talarico From: Rome, NY USA Posts: 630 Member Since: 06/01/05 |
posted March 15, 2006 9:20 AM Ajax uses client script to build elements and update the document object model on the page during a callback. Using standard controls, client script is not involved and the browser just parses the resultant HTML. In the case of thousands of elements being updated, one weakness of client script manipulation of the DOM is exposed. While not making excuses for Ajax, I do question the usability of an application that displays thousands or tens of thousands of rows in a control. What may be more user-friendly is offering a way to filter the results. For example, providing a dropdown that causes another to be populated based on the selection in the first. You can even repeat this process with several dropdowns. Strictly from a usability standpoint, you should fill dropdowns with less than 100 options. This also applies to populating a datagrid with thousands of rows. While it is possible to do, it may also slow down at large numbers (thousands+) of cells. Offering pagination or filtering options is less cumbersome for the user and faster to render. |
| jowi From: The Hague, Netherlands Posts: 3 Member Since: 03/15/06 |
posted March 15, 2006 10:51 AM Brian, thanks for your quick response, and you're absolutely right, this is mainly a user-interface problem, which should be dealt with in a better way. Even 100 items is way too much basically. |
| jowi From: The Hague, Netherlands Posts: 3 Member Since: 03/15/06 |
posted March 15, 2006 10:52 AM I ment John ;) |
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