diff --git a/Assets/Cryville/Common/Pdt/PdtInterpreter.cs b/Assets/Cryville/Common/Pdt/PdtInterpreter.cs
index ad6f6af..7eebc51 100644
--- a/Assets/Cryville/Common/Pdt/PdtInterpreter.cs
+++ b/Assets/Cryville/Common/Pdt/PdtInterpreter.cs
@@ -271,7 +271,9 @@ namespace Cryville.Common.Pdt {
 				if (prop == null) throw new MissingMemberException(string.Format("The property \"{0}\" is not found", pkey));
 				Type ptype = ReflectionHelper.GetMemberType(prop);
 				if (flag) {
-					using (var collection = new PairCollection(ReflectionHelper.GetValue(prop, result))) {
+					var origCollection = ReflectionHelper.GetValue(prop, result);
+					if (origCollection == null) origCollection = Activator.CreateInstance(ptype);
+					using (var collection = new PairCollection(origCollection)) {
 						var ktype = ptype.GetGenericArguments()[0];
 						var vtype = ptype.GetGenericArguments()[1];
 						object key = _binder.ChangeType(pkey, ktype, null);