Question

I have a DataGrid in my project. It doesn’t fit’s the width of the form, so the scrollBar appears. The DataGrid, on it’s initial state, displays a few columns and a part of the next column (which would appear after scrolling).

Is there any way, I can get the width of this, displaying part?

Answer 1

Ok, I had some time to dig more deeply in this problem. I’ve searched a few classes to see, how the Adobe was implementing those grid behavior (displaying columns partly). So, for those, who’ll need to deal with this, the needed part is in DataGrid.as file, method configureScrollBars .. actually, this part of it:

// if the last column is visible and partially offscreen (but it isn't the only
        // column) then adjust the column count so we can scroll to see it
        if (collectionHasRows && rowCount > 0 && colCount > 1 && 
            listItems[0][colCount - 1].x + 
            visibleColumns[colCount - 1].width > (displayWidth - listContent.x + viewMetrics.left))
            colCount--;
        else if (colCount > 1 && !collectionHasRows)
        {
            // the slower computation requires adding up the previous columns
            var colX:int = 0;
            for (var i:int = 0; i < visibleColumns.length; i++)
            {
                colX += visibleColumns[i].width;
            }
            if (colX > (displayWidth - listContent.x + viewMetrics.left))
                colCount--;
        }

That’s pretty much all code, that needed to catch and measure all those tricky divided cols in a grid 🙂