Add file that failed regression tests as a unit test.

OpenXmlFormats/Spreadsheet/Styles/CT_Dxfs.cs

@@ -12,7 +12,7 @@ namespace NPOI.OpenXmlFormats.Spreadsheet
 
     public class CT_Dxfs
     {
-
+        private Dictionary<int, string> dictAlternateContent = [];
         private List<CT_Dxf> dxfField;
 
         private uint countField;
@@ -23,12 +23,38 @@ namespace NPOI.OpenXmlFormats.Spreadsheet
             if (node == null)
                 return null;
             CT_Dxfs ctObj = new CT_Dxfs();
+            ctObj.InnerXml = node.InnerXml;
             ctObj.count = XmlHelper.ReadUInt(node.Attributes["count"]);
             ctObj.dxfField = new List<CT_Dxf>();
+            int index = 0;
             foreach (XmlNode childNode in node.ChildNodes)
             {
                 if (childNode.LocalName == "dxf")
                     ctObj.dxf.Add(CT_Dxf.Parse(childNode, namespaceManager));
+                else if(childNode.LocalName == "AlternateContent")
+                {
+                    //styleSheet:dxfs maybe have schema like this
+                    //mc:AlternateContent
+                    //    mc:Choice
+                    //        x:dxf
+                    //    mc:Fallback
+                    //        x:dxf
+                    foreach (XmlNode acChildNode in childNode.ChildNodes)
+                    {
+                        if (acChildNode.LocalName == "Fallback")
+                        {
+                            foreach(XmlNode fbChild in acChildNode.ChildNodes)
+                            {
+                                if(fbChild.LocalName == "dxf")
+                                {
+                                    ctObj.dxf.Add(CT_Dxf.Parse(fbChild, namespaceManager));
+                                }
+                            }
+                        }
+                    }
+                    ctObj.dictAlternateContent.Add(index, childNode.OuterXml);
+                }
+                index ++;
             }
             return ctObj;
         }
@@ -43,10 +69,17 @@ namespace NPOI.OpenXmlFormats.Spreadsheet
             if (this.dxf.Count > 0)
             {
                 sw.Write(">");
-                foreach (CT_Dxf x in this.dxf)
+                for(int i=0; i<this.dxf.Count;i++)
                 {
-                    x.Write(sw, "dxf");
+                    if(dictAlternateContent.TryGetValue(i, out string value))
+                        sw.Write(value);
+                    else
+                        dxf[i].Write(sw, "dxf");
                 }
+                //foreach(CT_Dxf x in this.dxf)
+                //{
+                //    x.Write(sw, "dxf");
+                //}
                 sw.Write(string.Format("</{0}>", nodeName));
             }
             else
@@ -59,6 +92,9 @@ namespace NPOI.OpenXmlFormats.Spreadsheet
         public CT_Dxfs()
         {
         }
+
+        public string InnerXml { get; set;}
+
         [XmlElement]
         public List<CT_Dxf> dxf
         {

ooxml/POIXMLDocumentPart.cs

@@ -249,6 +249,7 @@ namespace NPOI
             XmlNamespaceManager ns = new XmlNamespaceManager(nt);
             ns.AddNamespace(string.Empty, PackageNamespaces.SCHEMA_MAIN);
             ns.AddNamespace("d", PackageNamespaces.SCHEMA_MAIN);
+            ns.AddNamespace("x", PackageNamespaces.SCHEMA_MAIN);
             ns.AddNamespace("a", PackageNamespaces.SCHEMA_DRAWING);
             ns.AddNamespace("xdr", PackageNamespaces.SCHEMA_SHEETDRAWINGS);
             ns.AddNamespace("r", PackageNamespaces.SCHEMA_RELATIONSHIPS);

ooxml/XSSF/UserModel/XSSFSheet.cs

@@ -2222,7 +2222,7 @@ namespace NPOI.XSSF.UserModel
             double width = (col == null)
                 ? DefaultColumnWidth
                 : col.Width;
-            return (int)Math.Round(width * 256, 2);
+            return Math.Round(width * 256, 2);
         }
 
         /// <summary>

ooxml/XSSF/UserModel/XSSFTableStyle.cs

@@ -27,8 +27,7 @@ namespace NPOI.OOXML.XSSF.UserModel
                 if (element.dxfIdSpecified)
                 {
                     int idx = (int)element.dxfId;
-                    CT_Dxf dxf;
-                    dxf = dxfList[idx];
+                    CT_Dxf dxf = dxfList[idx];
                     int stripeSize = 0;
                     if (element.size!=0) stripeSize = (int)element.size;
                     if (dxf != null) dstyle = new XSSFDxfStyleProvider(dxf, stripeSize, colorMap);

testcases/ooxml/XSSF/Model/TestStylesTable.cs

@@ -326,7 +326,7 @@ namespace TestCases.XSSF.Model
         }
 
         [Test]
-        public void addDataFormatsBeyondUpperLimit()
+        public void AddDataFormatsBeyondUpperLimit()
         {
             XSSFWorkbook wb = new XSSFWorkbook();
 
@@ -360,7 +360,7 @@ namespace TestCases.XSSF.Model
         }
 
         [Test]
-        public void decreaseUpperLimitBelowCurrentNumDataFormats()
+        public void DecreaseUpperLimitBelowCurrentNumDataFormats()
         {
             XSSFWorkbook wb = new XSSFWorkbook();
 
@@ -392,6 +392,15 @@ namespace TestCases.XSSF.Model
                 wb.Close();
             }
         }
+        [Test]
+        public void TestLoadWithAlternateContent()
+        {
+            XSSFWorkbook workbook = XSSFTestDataSamples.OpenSampleWorkbook("style-alternate-content.xlsx");
+            ClassicAssert.IsNotNull(workbook.GetStylesSource());
 
+            StylesTable st = workbook.GetStylesSource();
+
+            ClassicAssert.IsNotNull(XSSFTestDataSamples.WriteOutAndReadBack(workbook));
+        }
     }
 }