Runtime csv field mappings

LINQtoCSV/CsvContext.cs

@@ -30,9 +30,18 @@ public class CsvContext
         /// <param name="fileDescription">
         /// Additional information how the input file is to be interpreted, such as the culture of the input dates.
         /// </param>
+        /// <param name="fieldNameOverrides">Runtime overrides for field names in the CSV file</param>
         /// <returns>
         /// Values read from the stream or file.
         /// </returns>
+        public IEnumerable<T> Read<T>(string fileName, CsvFileDescription fileDescription, Dictionary<string, string> fieldNameOverrides) where T : class, new()
+        {
+            // Note that ReadData will not be called right away, but when the returned 
+            // IEnumerable<T> actually gets accessed.
+
+            IEnumerable<T> ie = ReadData<T>(fileName, null, fileDescription, fieldNameOverrides);
+            return ie;
+        }
         public IEnumerable<T> Read<T>(string fileName, CsvFileDescription fileDescription) where T : class, new()
         {
             // Note that ReadData will not be called right away, but when the returned 
@@ -81,7 +90,8 @@ public class CsvContext
         private IEnumerable<T> ReadData<T>(
                     string fileName, 
                     StreamReader stream, 
-                    CsvFileDescription fileDescription) where T : class, new()
+                    CsvFileDescription fileDescription,
+                    Dictionary<string, string> fieldNameOverrides = null) where T : class, new()
         {
             // If T implements IDataRow, then we're reading raw data rows 
             bool readingRawDataRows = typeof(IDataRow).IsAssignableFrom(typeof(T));
@@ -169,7 +179,7 @@ private IEnumerable<T> ReadData<T>(
 
                     if (firstRow && fileDescription.FirstLineHasColumnNames)
                     {
-                        if (!readingRawDataRows) { fm.ReadNames(row); }
+                        if (!readingRawDataRows) { fm.ReadNames(row, fieldNameOverrides); }
                     }
                     else
                     {

LINQtoCSV/FieldMapper.cs

@@ -398,7 +398,7 @@ public FieldMapper_Reading(
         /// <param name="firstRow"></param>
         /// <returns></returns>
         ///
-        public void ReadNames(IDataRow row)
+        public void ReadNames(IDataRow row, Dictionary<string, string> fieldNameOverrides = null)
         {
             // It is now the order of the field names that determines
             // the order of the elements in m_IndexToInfo, instead of
@@ -410,7 +410,7 @@ public void ReadNames(IDataRow row)
 
             int currentNameIndex = 0;
             for (int i = 0; i < row.Count; i++) {
-                if (!m_NameToInfo.ContainsKey(row[i].Value)) {
+                if (string.IsNullOrEmpty(row[i].Value) || !(m_NameToInfo.ContainsKey(row[i].Value) || (fieldNameOverrides != null && fieldNameOverrides.ContainsKey(row[i].Value) && m_NameToInfo.ContainsKey(fieldNameOverrides[row[i].Value]))))  {
                     //If we have to ignore this column
                     if (m_fileDescription.IgnoreUnknownColumns) {
                         continue;
@@ -433,7 +433,13 @@ public void ReadNames(IDataRow row)
                     continue;
                 }
 
-                m_IndexToInfo[_mappingIndexes[i]] = m_NameToInfo[row[i].Value];
+                if (fieldNameOverrides == null || !fieldNameOverrides.ContainsKey(row[i].Value))
+                    m_IndexToInfo[_mappingIndexes[i]] = m_NameToInfo[row[i].Value];
+                else
+                {
+                    m_IndexToInfo[_mappingIndexes[i]] = m_NameToInfo[fieldNameOverrides[row[i].Value]];
+                }
+
 
                 if (m_fileDescription.EnforceCsvColumnAttribute && (!m_IndexToInfo[i].hasColumnAttribute)) {
                     // enforcing column attr, but this field/prop has no column attr.

TestConsoleApplication/ProductDataDto.cs

@@ -0,0 +1,13 @@
+namespace TestConsoleApplication
+{
+    public class ProductDataDto
+    {
+        public string Name { get; set; }
+
+        public string ShopsAvailable { get; set; }
+
+        public string HexProductCode { get; set; }
+
+        public string Description { get; set; }
+    }
+}

TestConsoleApplication/Program.cs

@@ -34,6 +34,26 @@ static void Main(string[] args)
 
             try
             {
+                var productFieldOverrides = new Dictionary<string, string>()
+                {
+                    { "name", "Name" },
+                    { "shopsAvailable", "ShopsAvailable" },
+                    { "code", "HexProductCode" },
+                    { "description", "Description" },
+                };
+
+                fileDescription_namesUs.IgnoreUnknownColumns = true;
+
+                var productDtos = cc.Read<ProductDataDto>("../../TestFiles/goodfile_us.csv", fileDescription_namesUs,
+                    productFieldOverrides);
+
+                foreach (var productDataDto in productDtos)
+                {
+                    Console.WriteLine($"{productDataDto.Name}, {productDataDto.Description}, {productDataDto.HexProductCode}, {productDataDto.ShopsAvailable}");
+                }
+
+                fileDescription_namesUs.IgnoreUnknownColumns = false;
+
                 dataRows_namesUs =
                     cc.Read<ProductData>("../../TestFiles/goodfile_us.csv", fileDescription_namesUs);
 

TestConsoleApplication/TestConsoleApplication.csproj

@@ -77,6 +77,7 @@
     <Reference Include="System.Xml" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="ProductDataDto.cs" />
     <Compile Include="ProductData_MissingFieldIndex.cs" />
     <Compile Include="ProductData_DuplicateIndices.cs" />
     <Compile Include="ProductData.cs" />