bugfix: ExcelToHtmlConverter throw exception when cell has background…

main/SS/UserModel/IndexedColors.cs

@@ -250,18 +250,31 @@ static IndexedColors()
             mappingIndex.Add(63, IndexedColors.Grey80Percent);
             mappingIndex.Add(64, IndexedColors.Automatic);
         }
+
+        public static IndexedColors TryValueOf(int index)
+        {
+            if (mappingIndex.ContainsKey(index))
+                return mappingIndex[index];
+
+            return null;
+        }
+
         public static IndexedColors ValueOf(string colorName)
         {
             if (mappingName.ContainsKey(colorName.ToLower()))
                 return mappingName[colorName.ToLower()];
 
             return null;
         }
+
         public static IndexedColors ValueOf(int index)
         {
-            if(mappingIndex.ContainsKey(index))
-                return mappingIndex[index];
-            throw new ArgumentException("Illegal IndexedColor index: " + index);
+            var indexedColors = TryValueOf(index);
+
+            if(indexedColors == null)
+                throw new ArgumentException("Illegal IndexedColor index: " + index);
+
+            return indexedColors;
         }
 
         /**

ooxml/SS/Converter/ExcelToHtmlConverter.cs

@@ -682,7 +682,7 @@ protected String BuildStyle(IWorkbook workbook, ICellStyle cellStyle)
                 else if (cellStyle.FillPattern == FillPattern.SolidForeground)
                 {
                     //cellStyle
-                    IndexedColors clr=IndexedColors.ValueOf(cellStyle.FillForegroundColor);
+                    IndexedColors clr=IndexedColors.TryValueOf(cellStyle.FillForegroundColor);
                     string hexstring=null;
                     if(clr!=null)
                     {
@@ -698,7 +698,7 @@ protected String BuildStyle(IWorkbook workbook, ICellStyle cellStyle)
                 }
                 else
                 {
-                    IndexedColors clr = IndexedColors.ValueOf(cellStyle.FillBackgroundColor);
+                    IndexedColors clr = IndexedColors.TryValueOf(cellStyle.FillBackgroundColor);
                     string hexstring = null;
                     if (clr != null)
                     {
@@ -752,7 +752,7 @@ private void BuildStyle_Border(IWorkbook workbook, StringBuilder style,
             }
             else 
             {
-                IndexedColors clr = IndexedColors.ValueOf(borderColor);
+                IndexedColors clr = IndexedColors.TryValueOf(borderColor);
                 if (clr != null)
                 {
                    borderStyle.Append(' ');
@@ -803,7 +803,7 @@ void BuildStyle_Font(IWorkbook workbook, StringBuilder style,
             }
             else
             {
-                IndexedColors clr = IndexedColors.ValueOf(font.Color);
+                IndexedColors clr = IndexedColors.TryValueOf(font.Color);
                 string hexstring = null;
                 if (clr != null)
                 {

testcases/ooxml/SS/Converter/TestExcelToHtmlConverterSuite.cs

@@ -1,5 +1,6 @@
 using NPOI.HSSF.UserModel;
 using NPOI.SS.Converter;
+using NPOI.XSSF.UserModel;
 using NUnit.Framework;
 using System;
 using System.Collections.Generic;
@@ -63,10 +64,36 @@ public void TestExcelToHtmlConverter()
         private void Test(string fileName)
         {
             HSSFWorkbook workbook;
-                workbook = ExcelToHtmlUtils.LoadXls(fileName);
-                ExcelToHtmlConverter excelToHtmlConverter = new ExcelToHtmlConverter();
-                excelToHtmlConverter.ProcessWorkbook(workbook);
-                excelToHtmlConverter.Document.Save(Path.ChangeExtension(fileName, "html")); ;
+            workbook = ExcelToHtmlUtils.LoadXls(fileName);
+            ExcelToHtmlConverter excelToHtmlConverter = new ExcelToHtmlConverter();
+            excelToHtmlConverter.ProcessWorkbook(workbook);
+            excelToHtmlConverter.Document.Save(Path.ChangeExtension(fileName, "html")); ;
+        }
+
+        [Test]
+        public void TestExcelToHtmlConverterWithBackground()
+        {
+            var fi = new FileInfo(@"..\..\..\..\test-data\spreadsheet\background_color.xlsx");
+            string fileName = fi.FullName;
+
+            XSSFWorkbook workbook;
+            FileStream inputStream = File.Open(fileName, FileMode.Open);
+            try
+            {
+                workbook = new XSSFWorkbook(inputStream);
+            }
+            finally
+            {
+                if (inputStream != null)
+                    inputStream.Close();
+
+                inputStream = null;                
+            }
+
+            ExcelToHtmlConverter excelToHtmlConverter = new ExcelToHtmlConverter();
+            excelToHtmlConverter.ProcessWorkbook(workbook);
+            excelToHtmlConverter.Document.Save(Path.ChangeExtension(fileName, "html"));
+
         }
     }
 }