Question

I’ve had EPPlus (Office Open XML) working on a Azure Web Role for some time now, but I’ve been experimenting with Azure Web Sites lately and there I’m getting a very weird error;

[DivideByZeroException: Attempted to divide by zero.]
   System.Decimal.FCallDivide(Decimal& d1, Decimal& d2) +0
   OfficeOpenXml.Drawing.ExcelDrawing.SetPixelWidth(Int32 pixels, Single dpi) +465
   Compliance.Net.CommonCode.PivotGenerator.GeneratePivotTable(ExcelWorksheet dataWorksheet, ExcelWorksheet pivotWorksheet, Int32 endRow)

I am getting this on the same data and code as is running on Azure Web Role.

Edit:
The offending lines look like this:

 var chart = pivotWorksheet.Drawings.AddChart("PivotChart", eChartType.ColumnClustered, pivotTable);
 chart.SetPosition(endRow + 2, 20, 1, 10);
 chart.SetSize(600, 400);

Please note that I have made sure that ‘endRow’ is > 1.

Any ideas?

Answer 1

Having had the same issue myself I’ve pulled the EPPlus source and done some sleuthing.

The issue is in ExcelWorkbook.cs line 283 which calls

System.Windows.Forms.TextRenderer.MeasureText(string,Font).Width

which appears to return Zero in an Azure website.

I’ve just added a line

if (_standardFontWidth == 0) _standardFontWidth = 7;

(7 was the value I was getting locally so it will do as my default – your mileage may vary) meaning I ended up with

    public decimal MaxFontWidth 
    {
        get
        {
            if (_standardFontWidth == decimal.MinValue)
            {
                var font = Styles.Fonts[0];
                System.Drawing.Font f = new System.Drawing.Font(font.Name, font.Size);
                _standardFontWidth=(decimal)(System.Windows.Forms.TextRenderer.MeasureText("00", f).Width - System.Windows.Forms.TextRenderer.MeasureText("0", f).Width);
            }
            if (_standardFontWidth == 0) _standardFontWidth = 7;
            return _standardFontWidth;
        }
    }

Of course this means building EPPlus from source, and you may have a different value for 7, but its a useful workaround for me!