1 files changed, 7 insertions, 1 deletions
diff --git a/csharp/ProtocolBuffers/ExtendableMessage.cs b/csharp/ProtocolBuffers/ExtendableMessage.cs
index c3b37dd5..a4a6e17e 100644
--- a/csharp/ProtocolBuffers/ExtendableMessage.cs
+++ b/csharp/ProtocolBuffers/ExtendableMessage.cs
@@ -67,12 +67,18 @@ namespace Google.ProtocolBuffers {
     }
 
     /// <summary>
-    /// Called by subclasses to check if all extensions are initialized.
+    /// Called to check if all extensions are initialized.
     /// </summary>
     protected bool ExtensionsAreInitialized {
       get { return extensions.IsInitialized; }      
     }
 
+    public override bool IsInitialized {
+      get {
+        return base.IsInitialized && ExtensionsAreInitialized;
+      }
+    }
+
     #region Reflection
     public override IDictionary<FieldDescriptor, object> AllFields {
       get {