diff --git a/csharp/src/Google.Protobuf.Test/Reflection/CustomOptionsTest.cs b/csharp/src/Google.Protobuf.Test/Reflection/CustomOptionsTest.cs
index 68b4d6af7cf8b..9469df7239b28 100644
--- a/csharp/src/Google.Protobuf.Test/Reflection/CustomOptionsTest.cs
+++ b/csharp/src/Google.Protobuf.Test/Reflection/CustomOptionsTest.cs
@@ -121,7 +121,7 @@ public void SimpleIntegerTest()
 
             var options = CustomOptions.Empty;
             options = options.ReadOrSkipUnknownField(input);
-
+            
             int intValue;
             Assert.True(options.TryGetInt32(1, out intValue));
             Assert.AreEqual(1234567, intValue);
@@ -147,7 +147,7 @@ public void SimpleStringTest()
 
             var options = CustomOptions.Empty;
             options = options.ReadOrSkipUnknownField(input);
-
+            
             string stringValue;
             Assert.True(options.TryGetString(1, out stringValue));
             Assert.AreEqual("value", stringValue);
@@ -195,7 +195,7 @@ public void OptionLocations()
             var messageOptions = TestMessageWithCustomOptions.Descriptor.CustomOptions;
             AssertOption(-56, messageOptions.TryGetInt32, MessageOpt1);
 
-            var fieldOptions = TestMessageWithCustomOptions.Descriptor.Fields["field1"] .CustomOptions;
+            var fieldOptions = TestMessageWithCustomOptions.Descriptor.Fields["field1"].CustomOptions;
             AssertOption(8765432109UL, fieldOptions.TryGetFixed64, FieldOpt1);
 
             var oneofOptions = TestMessageWithCustomOptions.Descriptor.Oneofs[0].CustomOptions;
diff --git a/src/google/protobuf/compiler/csharp/csharp_reflection_class.cc b/src/google/protobuf/compiler/csharp/csharp_reflection_class.cc
index 5ddd616e10f59..47d49c39daca1 100644
--- a/src/google/protobuf/compiler/csharp/csharp_reflection_class.cc
+++ b/src/google/protobuf/compiler/csharp/csharp_reflection_class.cc
@@ -122,6 +122,21 @@ void ReflectionClassGenerator::WriteIntroduction(io::Printer* printer) {
     printer->Indent();
     printer->Print("\n");
   }
+  
+  printer->Print("public static class Extensions {\n");
+  printer->Indent();
+  for (int i = 0; i < file_->extension_count(); ++i) {
+	  const FieldDescriptor* extension_field = file_->extension(i);
+	  string var_name = GetFieldConstantName(extension_field);
+
+	  printer->Print("public const int $var_name$ = $extension_id$;\n",
+		  "var_name", var_name,
+		  "extension_id", SimpleItoa(extension_field->number()));
+  }
+  printer->Outdent();
+  printer->Print("}\n");
+
+
 
   printer->Print(
     "/// <summary>Holder for reflection information generated from $file_name$</summary>\n"