Bug 203204 [Regression] Error occors when preview the attached report design as XLS [1203]
engine/org.eclipse.birt.report.engine.emitter.prototype.excel/src/org/eclipse/birt/report/engine/emitter/excel/ExcelWriter.java
.getProperty( StyleConstant.TEXT_UNDERLINE_PROP );
			String color = style.getProperty( StyleConstant.COLOR_PROP );
			writeFont( fontName, size, fontWeight, fontStyle, strikeThrough,
					underline, color );
			String bgColor = style
					.getProperty( StyleConstant.BACKGROUND_COLOR_PROP );
			writeBackGroudColor( bgColor );
		}
		writeDataFormat( style );
		writer.closeTag( "Style" );
	}
    
	public void writeDataFormat( StyleEntry style )
	{
		if ( style.getProperty(StyleConstant.DATA_TYPE_PROP ) == Data.DATE
				&& style.getProperty( StyleConstant.DATE_FORMAT_PROP ) != null )
		{
			writer.openTag( "NumberFormat" );
			writer.attribute( "ss:Format", style
					.getProperty( StyleConstant.DATE_FORMAT_PROP ) );
			writer.closeTag( "NumberFormat" );
		}
		
		if ( style.getProperty(StyleConstant.DATA_TYPE_PROP ) == Data.NUMBER
				&& style.getProperty( StyleConstant.NUMBER_FORMAT_PROP ) != null )
		{
			writer.openTag( "NumberFormat" );
			writer.attribute( "ss:Format", style
					.getProperty( StyleConstant.NUMBER_FORMAT_PROP ) );
			writer.closeTag( "NumberFormat" );