Potential fix for Issue #12 - pending testing

src/Simplexcel.TestApp/Program.cs

@@ -28,7 +28,7 @@ static void Main(string[] args)
             sheet.Cells[0, 2].Bold = true;
             sheet.Cells[0, 2].TextColor = Color.Red;
 
-            Cell cell = "BIU Big Blue";
+            Cell cell = "BIU & Big & Blue";
             cell.Bold = true;
             cell.Underline = true;
             cell.Italic = true;
@@ -55,6 +55,9 @@ static void Main(string[] args)
             cell2.FontSize = 18;
             sheet.Cells[0, 2] = cell2;
 
+            sheet.Cells[0, 6] = "👪";
+            sheet.Cells[0, 7] = "👨‍👩‍👧‍👦";
+
             wb.Add(sheet);
 
             var sheet2 = new Worksheet("Sheet 2");

src/Simplexcel.Tests/BugTests.cs

@@ -0,0 +1,28 @@
+using Simplexcel.XlsxInternal;
+using System.Linq;
+using Xunit;
+
+namespace Simplexcel.Tests
+{
+    public class BugTests
+    {
+        /// <summary>
+        /// https://github.com/mstum/Simplexcel/issues/12
+        /// 
+        /// SharedStrings _sanitizeRegex makes "&" in CellStrings impossible
+        /// </summary>
+        [Fact]
+        public void Issue12_AmpersandInCellValues()
+        {
+            var sharedStrings = new SharedStrings();
+            sharedStrings.GetStringIndex("Here & Now");
+            sharedStrings.GetStringIndex("&");
+            var xmlFile = sharedStrings.ToXmlFile();
+
+            var nodeValues = xmlFile.Content.Descendants(Namespaces.x + "t").Select(x => x.Value).ToList();
+
+            Assert.Contains("Here & Now", nodeValues);
+            Assert.Contains("&", nodeValues);
+        }
+    }
+}

src/Simplexcel.Tests/Simplexcel.Tests.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <TargetFramework>netcoreapp1.1</TargetFramework>
@@ -15,4 +15,8 @@
     <ProjectReference Include="..\Simplexcel\Simplexcel.csproj" />
   </ItemGroup>
 
+  <ItemGroup>
+    <Service Include="{82a7f48d-3b50-4b1e-b82e-3ada8210c358}" />
+  </ItemGroup>
+
 </Project>

src/Simplexcel/InternalsVisibleTo.cs

@@ -0,0 +1,2 @@
+using System.Runtime.CompilerServices;
+[assembly: InternalsVisibleTo("Simplexcel.Tests")]

src/Simplexcel/XlsxInternal/SharedStrings.cs

@@ -13,7 +13,6 @@ namespace Simplexcel.XlsxInternal
     internal class SharedStrings
     {
         private readonly Dictionary<string, int> _sharedStrings = new Dictionary<string, int>(StringComparer.Ordinal);
-        private static Regex _sanitizeRegex = new Regex("[\x00-\x08\x0B\x0C\x0E-\x1F\x26]", RegexOptions.Compiled);
 
         /// <summary>
         /// The number of Unique Strings
@@ -63,9 +62,11 @@ internal XmlFile ToXmlFile()
 
             foreach (var kvp in _sharedStrings.OrderBy(k => k.Value))
             {
-                var str = _sanitizeRegex.Replace(kvp.Key, string.Empty);
-                var se = new XElement(Namespaces.x + "si", new XElement(Namespaces.x + "t", str));
-                sst.Root.Add(se);
+                var tElem = new XElement(Namespaces.x + "t");
+                tElem.Value = kvp.Key;
+
+                var siElem = new XElement(Namespaces.x + "si", tElem);
+                sst.Root.Add(siElem);
             }
 
             file.Content = sst;