diff --git a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/CsharpDotNet2ClientCodegen.java b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/CsharpDotNet2ClientCodegen.java
index 404e01c145b..82d5a76a609 100644
--- a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/CsharpDotNet2ClientCodegen.java
+++ b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/CsharpDotNet2ClientCodegen.java
@@ -10,6 +10,8 @@
 import io.swagger.models.properties.Property;
 import io.swagger.codegen.CliOption;
 
+import org.apache.commons.lang3.StringUtils;
+
 import java.io.File;
 import java.util.Arrays;
 import java.util.HashMap;
@@ -233,11 +235,26 @@ public String toParamName(String name) {
 
     @Override
     public String toModelName(String name) {
+        if (!StringUtils.isEmpty(modelNamePrefix)) {
+            name = modelNamePrefix + "_" + name;
+        }
+
+        if (!StringUtils.isEmpty(modelNameSuffix)) {
+            name = name + "_" + modelNameSuffix;
+        }
+
         name = sanitizeName(name);
 
         // model name cannot use reserved keyword, e.g. return
         if (isReservedWord(name)) {
-            throw new RuntimeException(name + " (reserved word) cannot be used as a model name");
+            LOGGER.warn(name + " (reserved word) cannot be used as model name. Renamed to " + camelize("model_" + name));
+            name = "model_" + name; // e.g. return => ModelReturn (after camelize)
+        }
+
+        // model name starts with number
+        if (name.matches("^\\d.*")) {
+            LOGGER.warn(name + " (model name starts with number) cannot be used as model name. Renamed to " + camelize("model_" + name));
+            name = "model_" + name; // e.g. 200Response => Model200Response (after camelize)
         }
 
         // camelize the model name
@@ -284,12 +301,18 @@ public String getSwaggerType(Property p) {
 
     @Override
     public String toOperationId(String operationId) {
+        // throw exception if method name is empty (should not occur as an auto-generated method name will be used)
+        if (StringUtils.isEmpty(operationId)) {
+            throw new RuntimeException("Empty method name (operationId) not allowed");
+        }
+
         // method name cannot use reserved keyword, e.g. return
         if (isReservedWord(operationId)) {
-            throw new RuntimeException(operationId + " (reserved word) cannot be used as method name");
+            LOGGER.warn(operationId + " (reserved word) cannot be used as method name. Renamed to " + camelize(sanitizeName("call_" + operationId)));
+            operationId = "call_" + operationId;
         }
 
-        return camelize(operationId);
+        return camelize(sanitizeName(operationId));
     }
 
     @Override
diff --git a/samples/client/petstore/csharp-dotnet2/SwaggerClientTest/Lib/SwaggerClient/README.md b/samples/client/petstore/csharp-dotnet2/SwaggerClientTest/Lib/SwaggerClient/README.md
index 6cd17fe5c76..edb62683e0f 100644
--- a/samples/client/petstore/csharp-dotnet2/SwaggerClientTest/Lib/SwaggerClient/README.md
+++ b/samples/client/petstore/csharp-dotnet2/SwaggerClientTest/Lib/SwaggerClient/README.md
@@ -6,8 +6,8 @@ This C# SDK is automatically generated by the [Swagger Codegen](https://github.c
 
 - API version: 1.0.0
 - SDK version: 1.0.0
-- Build date: 2016-12-09T16:46:08.135+08:00
-- Build package: class io.swagger.codegen.languages.CsharpDotNet2ClientCodegen
+- Build date: 2017-01-22T16:52:29.599+08:00
+- Build package: io.swagger.codegen.languages.CsharpDotNet2ClientCodegen
 
 <a name="frameworks-supported"></a>
 ## Frameworks supported