Question

I Use Spreadsheetgear to generate an Excel Workbook.

My Workbook is very simple:

• I insert Strings in cells
• The first line is Bold
• I draw borders around the headers and between the columns.

At the end of the process, i call myRange.Columns.AutoFit(), then I save the workbook.

When I open it with Excel, the autofit is almost good, but it still miss around 1.2 width units in each columns.

Is this a bug in AutoFit() implementation or am I missing something ?

Answer 1

I actually asked SpreadsheetGear support about this as I was building my implementation about 6 months ago. I mentioned that b/c their AutoFit() was not fitting exactly right, that I was having to add a “fudge factor” to each column after autosizing.
Support’s response was essentially that it was a known discrepancy with Excel, that they dont classify as a bug. Here’s what they had to say to me:

The reason for auto-fit columns being slightly off between SpreadsheetGear and Excel is that the font metrics provided to us by .NET and GDI+ differ from those used in Excel. Because column dimensions are tied to fonts used in the workbook, and therefore font metrics, attempting to match Excel exactly just isn’t possible, unfortunately. We do our best to match Excel, but it is impossible to exactly match them in all cases.

Interestingly, Excel’s actually quite inconsistent with their font metric calculations; try using SpreadsheetGear to create a workbook with long runs of text, perhaps adding 40-50 “a” characters to a cell. Now save that workbook to disk and open it in Excel 2007 or 2010 use their zoom slider in the lower-right-hand corner to zoom in and out at different points and note that the text shifts around relative to the column width quite a bit. SpreadsheetGear is much more consistent with this type of scenario.

Regardless, your method of adding a little “fudge factor” to the column widths is the best workaround we can suggest. It is “hackish” but there’s simply nothing we can do to improve it since you’re dealing with two different environments and an inconsistent metrics in Excel itself.

And here’s the “fudge factor” that I used to widen the columns as needed:

ws.UsedRange.Columns.AutoFit()
For col As Integer = 0 To ws.UsedRange.ColumnCount - 1
    ws.Cells(1, col).ColumnWidth *= 1.
Next

In C#

ws.UsedRange.Columns.AutoFit()
for (int col = 0; col < ws.UsedRange.ColumnCount; col++)
    ws.Cells[1, col].ColumnWidth *= 1.15;