Add stylesheet to openxml excel file - openxml

Question

I'm trying to insert some styles in a excel file. Right now the data part works perfectly, but the style throws an error when I open the excel. It complains that the stylesheet file has an error in line 19 of the xml. I don't know what is wrong with that line. It is where the font collection node start.
Any ideas why...
This is the xml for the style
<?xml version="1.0" encoding="utf-8"?>
<x:styleSheet xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:x14ac="http://schemas.microsoft.com/office/spreadsheetml/2009/9/ac" xmlns:x="http://schemas.openxmlformats.org/spreadsheetml/2006/main" mc:Ignorable="x14ac">
<x:borders count="1">
<x:border>
<x:left style="thin">
<x:color indexed="64" rgb="000000" />
</x:left>
<x:right style="thin">
<x:color indexed="64" rgb="000000" />
</x:right>
<x:top style="thin">
<x:color indexed="64" rgb="000000" />
</x:top>
<x:bottom style="thin">
<x:color indexed="64" rgb="000000" />
</x:bottom>
</x:border>
</x:borders>
<x:fonts count="1">
<x:font>
<x:b />
<x:sz val="12" />
<x:color rgb="000000" />
<x:name val="Arial" />
</x:font>
</x:fonts>
<x:cellXfs>
<x:xf fontId="0" borderId="0" applyFont="1" applyBorder="1" />
<x:xf fontId="0" borderId="0" applyFont="1" applyBorder="1" />
<x:xf fontId="0" borderId="0" applyFont="1" applyBorder="1" />
<x:xf fontId="0" borderId="0" applyFont="1" applyBorder="1" />
<x:xf fontId="0" borderId="0" applyFont="1" applyBorder="1" />
<x:xf borderId="0" applyBorder="1" />
<x:xf borderId="0" applyBorder="1" />
<x:xf borderId="0" applyBorder="1" />
<x:xf fontId="0" borderId="0" applyFont="1" applyBorder="1" />
<x:xf borderId="0" applyBorder="1" />
<x:xf borderId="0" applyBorder="1" />
<x:xf borderId="0" applyBorder="1" />
<x:xf fontId="0" borderId="0" applyFont="1" applyBorder="1" />
<x:xf borderId="0" applyBorder="1" />
<x:xf borderId="0" applyBorder="1" />
<x:xf borderId="0" applyBorder="1" />
<x:xf fontId="0" borderId="0" applyFont="1" applyBorder="1" />
<x:xf borderId="0" applyBorder="1" />
<x:xf borderId="0" applyBorder="1" />
<x:xf borderId="0" applyBorder="1" />
<x:xf fontId="0" borderId="0" applyFont="1" applyBorder="1" />
<x:xf borderId="0" applyBorder="1" />
<x:xf borderId="0" applyBorder="1" />
<x:xf borderId="0" applyBorder="1" />
<x:xf fontId="0" borderId="0" applyFont="1" applyBorder="1" />
<x:xf borderId="0" applyBorder="1" />
<x:xf borderId="0" applyBorder="1" />
<x:xf borderId="0" applyBorder="1" />
<x:xf fontId="0" borderId="0" applyFont="1" applyBorder="1" />
<x:xf borderId="0" applyBorder="1" />
<x:xf borderId="0" applyBorder="1" />
<x:xf borderId="0" applyBorder="1" />
</x:cellXfs>
</x:styleSheet>
UPDATE
After some testing, googling, head banging.... I came up with the following stylesheet xml
<?xml version="1.0" encoding="utf-8"?>
<x:styleSheet xmlns:x="http://schemas.openxmlformats.org/spreadsheetml/2006/main" xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:x14ac="http://schemas.microsoft.com/office/spreadsheetml/2009/9/ac" xmlns:x16r2="http://schemas.microsoft.com/office/spreadsheetml/2015/02/main" xmlns:xr="http://schemas.microsoft.com/office/spreadsheetml/2014/revision" mc:Ignorable="x14ac x16r2 xr">
<x:fonts count="2" x14ac:knownFonts="1">
<x:font />
<x:font>
<x:b />
<x:sz val="12" />
<x:color rgb="FF000000" />
<x:name val="Arial" />
<x:family val="2" />
<x:scheme val="minor" />
</x:font>
</x:fonts>
<x:borders count="2">
<x:border />
<x:border>
<x:left style="thin">
<x:color rgb="FF000000" />
</x:left>
<x:right style="thin">
<x:color rgb="FF000000" />
</x:right>
<x:top style="thin">
<x:color rgb="FF000000" />
</x:top>
<x:bottom style="thin">
<x:color rgb="FF000000" />
</x:bottom>
</x:border>
</x:borders>
<x:cellXfs count="3">
<x:xf />
<x:xf fontId="1" borderId="1" applyFont="1" applyBorder="1" />
<x:xf borderId="1" applyBorder="1" />
</x:cellXfs>
</x:styleSheet>
Still excel complains that the file is corrupt after recovering the file it displays the styles applied to each cell gives the error "Repaired Records: Format from /xl/styles.xml part (Styles)" .
LibreOffice opens the file correctly, OPEN XML SDK 2.0 Productivity Tool validates the file as correct...Why excel complains.....
UPDATE
After playing around with the code I solved the problem.
This two questions also helped
Stylesheet 1
Stylesheet 2
It seems that there is an order to create the nodes, specially the cellStyleXfs and cellXfs, the cellStyleXfs as to come before the cellXfs
The working XML
<?xml version="1.0" encoding="utf-8"?>
<x:styleSheet xmlns:x="http://schemas.openxmlformats.org/spreadsheetml/2006/main" xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:x14ac="http://schemas.microsoft.com/office/spreadsheetml/2009/9/ac" xmlns:x16r2="http://schemas.microsoft.com/office/spreadsheetml/2015/02/main" xmlns:xr="http://schemas.microsoft.com/office/spreadsheetml/2014/revision" mc:Ignorable="x14ac x16r2 xr">
<x:fonts count="3" x14ac:knownFonts="1">
<x:font />
<x:font>
<x:b />
<x:sz val="12" />
<x:color rgb="FF000000" />
<x:name val="Arial" />
<x:family val="2" />
<x:scheme val="minor" />
</x:font>
<x:font>
<x:b />
<x:sz val="12" />
<x:color rgb="FFFF0000" />
<x:name val="Arial" />
<x:family val="2" />
<x:scheme val="minor" />
</x:font>
</x:fonts>
<x:fills count="1">
<x:fill />
</x:fills>
<x:borders count="2">
<x:border />
<x:border>
<x:left style="thin">
<x:color rgb="FF000000" />
</x:left>
<x:right style="thin">
<x:color rgb="FF000000" />
</x:right>
<x:top style="thin">
<x:color rgb="FF000000" />
</x:top>
<x:bottom style="thin">
<x:color rgb="FF000000" />
</x:bottom>
<x:diagonal />
</x:border>
</x:borders>
<x:cellStyleXfs count="1">
<x:xf numFmtId="0" fontId="0" fillId="0" borderId="0" xfId="0" />
</x:cellStyleXfs>
<x:cellXfs count="4">
<x:xf numFmtId="0" fontId="0" fillId="0" borderId="0" xfId="0" />
<x:xf numFmtId="0" fontId="1" fillId="0" borderId="1" xfId="0" applyNumberFormat="1" applyFont="1" applyFill="1" applyBorder="1" />
<x:xf numFmtId="0" fontId="2" fillId="0" borderId="1" xfId="0" applyNumberFormat="1" applyFont="1" applyFill="1" applyBorder="1" />
<x:xf numFmtId="0" fontId="0" fillId="0" borderId="1" xfId="0" applyNumberFormat="1" applyFont="1" applyFill="1" applyBorder="1" />
</x:cellXfs>
</x:styleSheet>

Answer 1

Excel is limited to a palette of 56 colors. The indexes are stored rather than the actual RGB value as you have provided. I don't know how you are generating the xmls, but your font node should look something like this:
<x:fonts count="1">
<x:font>
<x:b />
<x:sz val="12" />
<x:color theme="1" />
<x:name val="Arial" />
</x:font>
</x:fonts>
If you use C# or VBA then you can set Colors to your liking by accessing Workbook.Colors Property
EDIT
Like for fonts, borders need to store indexes rather than the actual RGB value as you have provided. Your border node should be something like:
<x:left style="thin">
<x:color indexed="64" />
</x:left>
also note, borders need to defined in the correct order: left, right, top, bottom, diagonal. Seems correct in your xml but nevertheless thought of mentioning it here.
This is a good example