diff --git a/compiler/cpp/src/generate/t_csharp_generator.cc b/compiler/cpp/src/generate/t_csharp_generator.cc
index 48df1b0..fceec84 100644
--- a/compiler/cpp/src/generate/t_csharp_generator.cc
+++ b/compiler/cpp/src/generate/t_csharp_generator.cc
@@ -321,12 +321,12 @@
   if (members.size() > 0) {
     out <<
       endl <<
-      indent() << "public Isset __isset = new Isset();" << endl <<
-      indent() << "public sealed class Isset {" << endl;
+      indent() << "public Isset __isset;" << endl <<
+      indent() << "public struct Isset {" << endl;
     indent_up();
     for (m_iter = members.begin(); m_iter != members.end(); ++m_iter) {
       indent(out) <<
-        "public bool " << (*m_iter)->get_name() << " = false;" << endl;
+        "public bool " << (*m_iter)->get_name() << ";" << endl;
     }
 
     indent_down();
@@ -593,7 +593,7 @@
     t_type* ttype = (*f_iter)->get_type();
     if (ttype->is_xception() || ttype->is_struct()) {
       indent(out) <<
-        "sb.Append(this." << (*f_iter)->get_name() << ".ToString());" << endl;
+        "sb.Append(this." << (*f_iter)->get_name() << "== null ? \"<null>\" : "<< "this." << (*f_iter)->get_name() << ".ToString());" << endl;
     } else {
       indent(out) <<
         "sb.Append(this." << (*f_iter)->get_name() << ");" << endl;
@@ -1384,7 +1384,7 @@
   }
 
   if (ttype->is_base_type()) {
-    return base_type_name(((t_base_type*)ttype)->get_base(), in_container);
+    return base_type_name((t_base_type*)ttype, in_container);
   } else if (ttype->is_map()) {
     t_map *tmap = (t_map*) ttype;
     return "Dictionary<" + type_name(tmap->get_key_type(), true) +
diff --git a/lib/csharp/src/Protocol/TField.cs b/lib/csharp/src/Protocol/TField.cs
index f18381f..9329530 100644
--- a/lib/csharp/src/Protocol/TField.cs
+++ b/lib/csharp/src/Protocol/TField.cs
@@ -16,12 +16,8 @@
 
 namespace Thrift.Protocol
 {
-	public class TField
+	public struct TField
 	{
-		public TField()
-		{
-		}
-
 		public TField(string name, TType type, short id)
 		{
 			Name = name;
diff --git a/lib/csharp/src/Protocol/TList.cs b/lib/csharp/src/Protocol/TList.cs
index ff6aa53..72056cb 100644
--- a/lib/csharp/src/Protocol/TList.cs
+++ b/lib/csharp/src/Protocol/TList.cs
@@ -16,12 +16,8 @@
 
 namespace Thrift.Protocol
 {
-	public class TList
+	public struct TList
 	{
-		public TList()
-		{
-		}
-
 		public TList(TType elementType, int count)
 		{
 			ElementType = elementType;
diff --git a/lib/csharp/src/Protocol/TMap.cs b/lib/csharp/src/Protocol/TMap.cs
index 495bf7c..586aa4f 100644
--- a/lib/csharp/src/Protocol/TMap.cs
+++ b/lib/csharp/src/Protocol/TMap.cs
@@ -16,12 +16,8 @@
 
 namespace Thrift.Protocol
 {
-	public class TMap
+	public struct TMap
 	{
-		public TMap()
-		{
-		}
-
 		public TMap(TType keyType, TType valueType, int count)
 		{
 			KeyType = keyType;
diff --git a/lib/csharp/src/Protocol/TMessage.cs b/lib/csharp/src/Protocol/TMessage.cs
index 60df660..a9522ff 100644
--- a/lib/csharp/src/Protocol/TMessage.cs
+++ b/lib/csharp/src/Protocol/TMessage.cs
@@ -16,12 +16,8 @@
 
 namespace Thrift.Protocol
 {
-	public class TMessage
+	public struct TMessage
 	{
-		public TMessage()
-		{
-		}
-
 		public TMessage(string name, TMessageType type, int seqid)
 		{
 			Name = name;
diff --git a/lib/csharp/src/Protocol/TProtocolException.cs b/lib/csharp/src/Protocol/TProtocolException.cs
index 0941a81..db38d88 100644
--- a/lib/csharp/src/Protocol/TProtocolException.cs
+++ b/lib/csharp/src/Protocol/TProtocolException.cs
@@ -1,6 +1,5 @@
 using System;
 using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 
 namespace Thrift.Protocol
diff --git a/lib/csharp/src/Protocol/TSet.cs b/lib/csharp/src/Protocol/TSet.cs
index c4c6fc3..1f172e4 100644
--- a/lib/csharp/src/Protocol/TSet.cs
+++ b/lib/csharp/src/Protocol/TSet.cs
@@ -16,12 +16,8 @@
 
 namespace Thrift.Protocol
 {
-	public class TSet
+	public struct TSet
 	{
-		public TSet()
-		{
-		}
-
 		public TSet(TType elementType, int count)
 		{
 			ElementType = elementType;
diff --git a/lib/csharp/src/Protocol/TStruct.cs b/lib/csharp/src/Protocol/TStruct.cs
index 88f12df..000ebf1 100644
--- a/lib/csharp/src/Protocol/TStruct.cs
+++ b/lib/csharp/src/Protocol/TStruct.cs
@@ -15,12 +15,8 @@
 
 namespace Thrift.Protocol
 {
-	public class TStruct
+	public struct TStruct
 	{
-		public TStruct()
-		{
-		}
-
 		public TStruct(string name)
 		{
 			Name = name;