CsvSerializer respects the configured CsvConfig.DateTimeFormatString

src/ServiceStack.Text/CsvConfig.cs

@@ -110,14 +110,31 @@ public static string RowSeparatorString
                 ResetEscapeStrings();
 			}
 		}
-
+
+		[ThreadStatic] 
+		private static string tsDateTimeFormatString;
+		private static string sDateTimeFormatString;
+		public static string DateTimeFormatString
+		{
+			get
+			{
+				return tsDateTimeFormatString ?? sDateTimeFormatString ?? "";
+			}
+			set
+			{
+				tsDateTimeFormatString = value;
+				if (sDateTimeFormatString == null) sDateTimeFormatString = value;
+			}
+		}
+
 		public static void Reset()
 		{
 			tsItemSeperatorString = sItemSeperatorString = null;
 			tsItemDelimiterString = sItemDelimiterString = null;
 			tsEscapedItemDelimiterString = sEscapedItemDelimiterString = null;
 			tsRowSeparatorString = sRowSeparatorString = null;
 		    tsEscapeStrings = sEscapeStrings = null;
+            tsDateTimeFormatString = sDateTimeFormatString = null;
 		}
 
     }

src/ServiceStack.Text/TextExtensions.cs

@@ -31,6 +31,23 @@ public static string ToCsvField(this string text)
                              );
         }
 
+        public static string ToCsvField(this DateTime value)
+        {
+            return !JsWriter.HasAnyEscapeChars(value.ToString())
+                        ? value.ToString(CsvConfig.DateTimeFormatString)
+                        : string.Concat
+                                (
+                                    JsWriter.QuoteString,
+                                    value.ToString(CsvConfig.DateTimeFormatString).Replace(JsWriter.QuoteString, TypeSerializer.DoubleQuoteString),
+                                    JsWriter.QuoteString
+                                );
+        }
+
+        public static string ToCsvField(this DateTime? value)
+        {
+	        return value.HasValue ? value.Value.ToCsvField() : null;
+        }
+
         public static object ToCsvField(this object text)
         {
             return text == null || !JsWriter.HasAnyEscapeChars(text.ToString())

tests/ServiceStack.Text.Tests/CsvStreamTests.cs

@@ -179,6 +179,39 @@ public void Can_convert_to_csv_field()
 			Assert.That("7,7.1".ToCsvField(), Is.EqualTo("\"7,7.1\""));
 			Assert.That("\"7,7.1\"".ToCsvField(), Is.EqualTo("\"\"\"7,7.1\"\"\""));
 		}
+
+        [Test]
+        public void Can_convert_to_csv_field_from_datetime_respecting_configured_datetimeformat()
+        {
+            var dateTime = DateTime.Now;
+            var testCases = new[] { "yyyy-MM-ddTHH:mm:ss.fff zzzz", "MM/dd/yyyy", "dd/MM/yyyy", "HH:mm:ss", "arbitrary string" };
+            foreach (var format in testCases)
+            {
+                CsvConfig.DateTimeFormatString = format;
+                Assert.That(dateTime.ToCsvField(),Is.EqualTo("\"" + dateTime.ToString(format) + "\""));
+            }
+        }
+
+        [Test]
+        public void Can_convert_to_csv_field_from_nullabledatetime_respecting_configured_datetimeformat()
+        {
+            DateTime? dateTime = DateTime.Now;
+            var testCases = new[] { "yyyy-MM-ddTHH:mm:ss.fff zzzz", "MM/dd/yyyy", "dd/MM/yyyy", "HH:mm:ss", "arbitrary string" };
+            foreach (var format in testCases)
+            {
+                CsvConfig.DateTimeFormatString = format;
+                Assert.That(dateTime.ToCsvField(), Is.EqualTo("\"" + dateTime.Value.ToString(format) + "\""));
+            }
+            DateTime? nullDateTime = null;
+            Assert.That(nullDateTime.ToCsvField(), Is.EqualTo(null));
+        }
+
+        [Test]
+        public void Can_convert_to_csv_field_from_datetime_without_a_configured_datetimeformat()
+        {
+            CsvConfig.Reset();
+            Assert.That(DateTime.Now.ToCsvField(), Is.EqualTo("\"" + DateTime.Now + "\""));
+        }
 
 		[Test]
 		public void Can_convert_to_csv_field_pipe_separator()