diff --git a/modules/swagger-codegen/src/main/resources/csharp/model.mustache b/modules/swagger-codegen/src/main/resources/csharp/model.mustache
index 96e17d8d1d3..be02f983be9 100644
--- a/modules/swagger-codegen/src/main/resources/csharp/model.mustache
+++ b/modules/swagger-codegen/src/main/resources/csharp/model.mustache
@@ -4,6 +4,7 @@ using System.IO;
 using System.Text;
 using System.Collections;
 using System.Collections.Generic;
+using System.Collections.ObjectModel;
 using System.Runtime.Serialization;
 using Newtonsoft.Json;
 
diff --git a/modules/swagger-codegen/src/test/java/io/swagger/codegen/csharp/CSharpClientOptionsTest.java b/modules/swagger-codegen/src/test/java/io/swagger/codegen/csharp/CSharpClientOptionsTest.java
index ab8f2806512..da1b7ef7ea2 100644
--- a/modules/swagger-codegen/src/test/java/io/swagger/codegen/csharp/CSharpClientOptionsTest.java
+++ b/modules/swagger-codegen/src/test/java/io/swagger/codegen/csharp/CSharpClientOptionsTest.java
@@ -42,6 +42,10 @@ public class CSharpClientOptionsTest extends AbstractOptionsTest {
             times = 1;
             clientCodegen.setPackageGuid(CSharpClientOptionsProvider.PACKAGE_GUID_VALUE);
             times = 1;
+            clientCodegen.setUseCollection(false);
+            times = 1;
+            clientCodegen.setReturnICollection(false);
+            times = 1;
         }};
     }
 }