Changes in RTM and the ListView.layout.groupInfo property

Question

Hi,

I just updated my application to RTM and i'm running into an issue with ListView that have different templates / sizes. In the samples:

http://code.msdn.microsoft.com/windowsapps/ListView-item-templates-7d74826f

A groupInfo property is set to:

        groupInfo : function () {
            return {
                enableCellSpanning: true,
                cellWidth: 250,
                cellHeight: 250
            };
        },

Which worked well in RC. Now I get an exception in UI.js:

Exception is about to be caught by JavaScript library code at line 17565, column 25 in ms-appx://microsoft.winjs.1.0/js/ui.js
0x800a01b6 - JavaScript runtime error: Object doesn't support property or method '_getGroup'

Here are the lines where it crashes:

// For multisize instead of using the first item size use the slot size of the first group.
                    var groupInfo;
                    if (typeof that._groupInfo === "function") {
                        var group0 = that._getGroup(0);
                        if (group0) {
                            groupInfo = that.groupInfo(group0.userData);
                        }
                    } else {
                        groupInfo = that._groupInfo;
                    }

It looks like it would be normal that it would crash because the _getGroup function is not defined in my object. I checked the samples and it's still the same code.

Should I add a _getGroup method to my object? What would it contain?

Thanks for your help!

Fabien

Answer 1

Hi Fabien,

I cannot tell what is going on from so little code.  Did you notice that now the groupInfo() in the sample looks like this?

// Enable cell spanning in ListView and specify 
// the cellWidth and cellHeight for the items 
var groupInfo = WinJS.Utilities.markSupportedForProcessing(function groupInfo() { 
    return { 
        enableCellSpanning: true, 
        cellWidth: 310, 
        cellHeight: 80 
    }; 
}); 

-Jeff

---

Jeff Sanders (MSFT)

Answer 2

Hello Jeff,

Yes, they added the markSupportedForProcessing for RTM but it's not necessary in my case because groupInfo is defined in a .define(...) block which automatically mark functions supportedForProcessing.

I found a way out of this problem, i actually don't need to have different sized elements when in snap mode because big elements don't even fit so I just don't assign groupInfo when snapped

Nevermind :)

Fabien