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GW BASIC in your browser!

By , 05/01/2012 1:33 PM

Classic comes alive

Now this just bring a nostalgic tear to your eye. Cory Smith of AddressOf implemented Classic DOS GW BASIC entirely in Silverlight. It’s beautiful, give it a go!

‘this.Column.Band’ is null or not an object error in UltraWebGrid filtering

By , 05/01/2012 12:11 PM

When you filter Infragistics UltraWebGrid by clicking Filter icon in the column header – dropdown with filter values appears. Normally if you click elsewhere on the page – dropdown disappears. But sometimes it doesn’t, for example if you click an element that invokes a JavaScript function. Filter dropdown stays open and this could cause problems – when grid refreshes (and possibly other actions are performed) error is thrown:

‘this.Column.Band’ is null or not an object

The solution to this is to close filter dropdown ourselves. Put these lines into your client-side code whenever clicking outside the filter doesn’t close it:

var aGridCols = igtbl_getGridById('xMyGrid').Bands[0].Columns
   for (var I = 0; I < aGridCols.length; I++)
      aGridCols[I].showFilterDropDown(false);

Here we’re looping thru grids column collection (This example assumes grid is in Flat or OutlookGroupBy mode, if your grid is hierarchical, you will have to loop thru band collection as well). For every column we pass False to showFilterDropDown method which (probably showing Infragistics cute sense of humor) hides filter dropdown if it is open. If dropdown is hidden for the column already – nothing happens.

As a result opened filter dropdown is now always closed prior to previously offending action and the error doesn’t happen.

Speed up UltraWebGrid rendering on rebind

By , 05/01/2012 11:38 AM

If you’re using Infragistics UltraWebGrid with it’s property Browser="Xml", you may find yourself living in a shotgun shack in a strange situation: When grid is rebinding – it takes (comparatively) short time to do server-side processing and then a very long time to render grid in the browser.

In my case it was most felt when grid (which had ViewType="OutlookGroupBy") was initially grouped with a lot of data in each group and then ungrouped back into flat view when user dragged last group column out. Using IE9 built-in developer tools I ran JavaScript profiler I found that culprit was Infragistics JS function “disposeNode” which was called numerous times and had worst both inclusive and exclusive execution time. Continue reading 'Speed up UltraWebGrid rendering on rebind'»

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