Unable to use multiple fonts with OpenXMl Cell styling - asp.net

Question

I have two different fonts defined in the style sheet but If I use the second style with StyleIndex=1 . I am unable to open the generated spread sheet. Any help would be greatly appreciated
My code
Private Function GenerateStyleSheet() As Stylesheet
Dim ss As Stylesheet = New Stylesheet()
Dim fonts1 As Fonts = New Fonts()
Dim f1 As Font = New Font()
Dim f1Size As FontSize = New FontSize()
f1Size.Val = 11D
f1.Append(f1Size)
Dim f2 As Font = New Font()
Dim b2 As Bold = New Bold()
Dim f2Size As FontSize = New FontSize()
f2Size.Val = 11D
f2.Append(b2)
f2.Append(f2Size)
fonts1.Append(f1)
fonts1.Append(f2)
fonts1.Count = fonts1.ChildElements.Count
ss.Append(fonts1)
Return ss
End Function
Function getBoldTextCell(ByVal cell As String, ByRef row As Row, ByVal val As String) As Row
Dim refCell As Cell = Nothing
Dim newCell As New Cell()
newCell.StyleIndex = 1 // 0 works
newCell.CellReference = cell
row.InsertBefore(newCell, refCell)
newCell.CellValue = New CellValue(val)
newCell.DataType = New EnumValue(Of CellValues)(CellValues.String)
Return (row)
End Function
XML Code:
<x:row xmlns:x="http://schemas.openxmlformats.org/spreadsheetml/2006/main">
<x:c r="A1" s="0" t="str">
<x:v>Request #</x:v>
</x:c>
<x:c r="B1" t="str">
<x:v>1</x:v>
</x:c>
</x:row>
Style Code:
<x:fonts count="2" xmlns:x="http://schemas.openxmlformats.org/spreadsheetml/2006/main">
<x:font>
<x:sz val="11" />
</x:font>
<x:font>
<x:b />
<x:sz val="11" />
</x:font>
</x:fonts>

Answer 1

You cannot define styles like that . You need to create a Style with Fonts , Fills , Borders and create cellformats from defined Fonts , Fills , Borders as given below.
// <Fonts>
Font font0 = new Font(); // Default font
Font font1 = new Font(); // Bold font
Bold bold = new Bold();
font1.Append(bold);
Fonts fonts = new Fonts(); // <APENDING Fonts>
fonts.Append(font0);
fonts.Append(font1);
// <Fills>
Fill fill0 = new Fill(); // Default fill
Fills fills = new Fills(); // <APENDING Fills>
fills.Append(fill0);
// <Borders>
Border border0 = new Border(); // Defualt border
Borders borders = new Borders(); // <APENDING Borders>
borders.Append(border0);
// <CellFormats>
CellFormat cellformat0 = new CellFormat() { FormatId = 0, FillId = 0, BorderId = 0 };
CellFormat cellformat1 = new CellFormat(new Alignment() { Horizontal HorizontalAlignmentValues.Center, Vertical = VerticalAlignmentValues.Center }) { FontId = 1 };
// <APENDING CellFormats>
CellFormats cellformats = new CellFormats();
cellformats.Append(cellformat0);
cellformats.Append(cellformat1);
// Append FONTS, FILLS , BORDERS & CellFormats to stylesheet <Preserve the ORDER>
workbookstylesheet.Append(fonts);
workbookstylesheet.Append(fills);
workbookstylesheet.Append(borders);
workbookstylesheet.Append(cellformats);
And later when defining cells , add style refference as
cell.StyleIndex=0 ; // Default style
cell1.StyleIndex=1 ; // Our defined style 1