diff --git a/modules/swagger-codegen/src/main/resources/csharp/ApiClient.mustache b/modules/swagger-codegen/src/main/resources/csharp/ApiClient.mustache
index 883a635472d..87d55ab3f6e 100644
--- a/modules/swagger-codegen/src/main/resources/csharp/ApiClient.mustache
+++ b/modules/swagger-codegen/src/main/resources/csharp/ApiClient.mustache
@@ -10,7 +10,6 @@ using System.Net;
 using System.Text;
 using Newtonsoft.Json;
 using RestSharp;
-using RestSharp.Extensions;
 
 namespace {{packageName}}.Client
 {
@@ -171,7 +170,7 @@ namespace {{packageName}}.Client
         /// <returns>Escaped string.</returns>
         public string EscapeString(string str)
         {
-            return RestSharp.Extensions.StringExtensions.UrlEncode(str);
+            return UrlEncode(str);
         }
     
         /// <summary>
@@ -183,9 +182,9 @@ namespace {{packageName}}.Client
         public FileParameter ParameterToFile(string name, Stream stream)
         {
             if (stream is FileStream)
-                return FileParameter.Create(name, stream.ReadAsBytes(), Path.GetFileName(((FileStream)stream).Name));
+                return FileParameter.Create(name, ReadAsBytes(stream), Path.GetFileName(((FileStream)stream).Name));
             else
-                return FileParameter.Create(name, stream.ReadAsBytes(), "no_file_name_provided");
+                return FileParameter.Create(name, ReadAsBytes(stream), "no_file_name_provided");
         }
     
         /// <summary>
@@ -365,6 +364,62 @@ namespace {{packageName}}.Client
         public static dynamic ConvertType(dynamic source, Type dest) {
             return Convert.ChangeType(source, dest);
         }
+
+        /// <summary>
+        /// Convert stream to byte array
+        /// Credit/Ref: http://stackoverflow.com/a/221941/677735
+        /// </summary>
+        /// <param name="input">Input stream to be converted</param>
+        /// <returns>Byte array</returns>
+        public static byte[] ReadAsBytes(Stream input)
+        {
+            byte[] buffer = new byte[16*1024];
+            using (MemoryStream ms = new MemoryStream())
+            {
+                int read;
+                while ((read = input.Read(buffer, 0, buffer.Length)) > 0)
+                {
+                    ms.Write(buffer, 0, read);
+                }
+                return ms.ToArray();
+            }
+        }
+
+        /// <summary>
+        /// URL encode a string
+        /// Credit/Ref: https://github.com/restsharp/RestSharp/blob/master/RestSharp/Extensions/StringExtensions.cs#L50
+        /// </summary>
+        /// <param name="input">String to be URL encoded</param>
+        /// <returns>Byte array</returns>
+        public static string UrlEncode(string input)
+        {
+            const int maxLength = 32766;
+
+            if (input == null)
+            {
+                throw new ArgumentNullException("input");
+            }
+
+            if (input.Length <= maxLength)
+            {
+                return Uri.EscapeDataString(input);
+            }
+
+            StringBuilder sb = new StringBuilder(input.Length * 2);
+            int index = 0;
+
+            while (index < input.Length)
+            {
+                int length = Math.Min(input.Length - index, maxLength);
+                string subString = input.Substring(index, length);
+
+                sb.Append(Uri.EscapeDataString(subString));
+                index += subString.Length;
+            }
+
+            return sb.ToString();
+        }
+
   
     }
 }
diff --git a/samples/client/petstore/csharp/SwaggerClientTest/Lib/SwaggerClient/src/main/csharp/IO/Swagger/Client/ApiClient.cs b/samples/client/petstore/csharp/SwaggerClientTest/Lib/SwaggerClient/src/main/csharp/IO/Swagger/Client/ApiClient.cs
index 049c1ef74d8..36217fde02d 100644
--- a/samples/client/petstore/csharp/SwaggerClientTest/Lib/SwaggerClient/src/main/csharp/IO/Swagger/Client/ApiClient.cs
+++ b/samples/client/petstore/csharp/SwaggerClientTest/Lib/SwaggerClient/src/main/csharp/IO/Swagger/Client/ApiClient.cs
@@ -10,7 +10,6 @@ using System.Net;
 using System.Text;
 using Newtonsoft.Json;
 using RestSharp;
-using RestSharp.Extensions;
 
 namespace IO.Swagger.Client
 {
@@ -171,7 +170,7 @@ namespace IO.Swagger.Client
         /// <returns>Escaped string.</returns>
         public string EscapeString(string str)
         {
-            return RestSharp.Extensions.StringExtensions.UrlEncode(str);
+            return UrlEncode(str);
         }
     
         /// <summary>
@@ -183,9 +182,9 @@ namespace IO.Swagger.Client
         public FileParameter ParameterToFile(string name, Stream stream)
         {
             if (stream is FileStream)
-                return FileParameter.Create(name, stream.ReadAsBytes(), Path.GetFileName(((FileStream)stream).Name));
+                return FileParameter.Create(name, ReadAsBytes(stream), Path.GetFileName(((FileStream)stream).Name));
             else
-                return FileParameter.Create(name, stream.ReadAsBytes(), "no_file_name_provided");
+                return FileParameter.Create(name, ReadAsBytes(stream), "no_file_name_provided");
         }
     
         /// <summary>
@@ -369,6 +368,62 @@ namespace IO.Swagger.Client
         public static dynamic ConvertType(dynamic source, Type dest) {
             return Convert.ChangeType(source, dest);
         }
+
+        /// <summary>
+        /// Convert stream to byte array
+        /// Credit/Ref: http://stackoverflow.com/a/221941/677735
+        /// </summary>
+        /// <param name="input">Input stream to be converted</param>
+        /// <returns>Byte array</returns>
+        public static byte[] ReadAsBytes(Stream input)
+        {
+            byte[] buffer = new byte[16*1024];
+            using (MemoryStream ms = new MemoryStream())
+            {
+                int read;
+                while ((read = input.Read(buffer, 0, buffer.Length)) > 0)
+                {
+                    ms.Write(buffer, 0, read);
+                }
+                return ms.ToArray();
+            }
+        }
+
+        /// <summary>
+        /// URL encode a string
+        /// Credit/Ref: https://github.com/restsharp/RestSharp/blob/master/RestSharp/Extensions/StringExtensions.cs#L50
+        /// </summary>
+        /// <param name="input">String to be URL encoded</param>
+        /// <returns>Byte array</returns>
+        public static string UrlEncode(string input)
+        {
+            const int maxLength = 32766;
+
+            if (input == null)
+            {
+                throw new ArgumentNullException("input");
+            }
+
+            if (input.Length <= maxLength)
+            {
+                return Uri.EscapeDataString(input);
+            }
+
+            StringBuilder sb = new StringBuilder(input.Length * 2);
+            int index = 0;
+
+            while (index < input.Length)
+            {
+                int length = Math.Min(input.Length - index, maxLength);
+                string subString = input.Substring(index, length);
+
+                sb.Append(Uri.EscapeDataString(subString));
+                index += subString.Length;
+            }
+
+            return sb.ToString();
+        }
+
   
     }
 }
diff --git a/samples/client/petstore/csharp/SwaggerClientTest/bin/Debug/SwaggerClientTest.dll b/samples/client/petstore/csharp/SwaggerClientTest/bin/Debug/SwaggerClientTest.dll
index c292bea9bad..c975e54d4be 100755
Binary files a/samples/client/petstore/csharp/SwaggerClientTest/bin/Debug/SwaggerClientTest.dll and b/samples/client/petstore/csharp/SwaggerClientTest/bin/Debug/SwaggerClientTest.dll differ
diff --git a/samples/client/petstore/csharp/SwaggerClientTest/bin/Debug/SwaggerClientTest.dll.mdb b/samples/client/petstore/csharp/SwaggerClientTest/bin/Debug/SwaggerClientTest.dll.mdb
index f63c1d21fe3..5c1092d07fc 100644
Binary files a/samples/client/petstore/csharp/SwaggerClientTest/bin/Debug/SwaggerClientTest.dll.mdb and b/samples/client/petstore/csharp/SwaggerClientTest/bin/Debug/SwaggerClientTest.dll.mdb differ
diff --git a/samples/client/petstore/csharp/SwaggerClientTest/obj/Debug/SwaggerClientTest.csproj.FilesWrittenAbsolute.txt b/samples/client/petstore/csharp/SwaggerClientTest/obj/Debug/SwaggerClientTest.csproj.FilesWrittenAbsolute.txt
index 286fb333c48..3ed0e98c4f7 100644
--- a/samples/client/petstore/csharp/SwaggerClientTest/obj/Debug/SwaggerClientTest.csproj.FilesWrittenAbsolute.txt
+++ b/samples/client/petstore/csharp/SwaggerClientTest/obj/Debug/SwaggerClientTest.csproj.FilesWrittenAbsolute.txt
@@ -1,8 +1,8 @@
-/Users/williamcheng/Code/swagger-codegen/samples/client/petstore/csharp/SwaggerClientTest/obj/Debug/.NETFramework,Version=v4.5.AssemblyAttribute.cs
-/Users/williamcheng/Code/swagger-codegen/samples/client/petstore/csharp/SwaggerClientTest/bin/Debug/Newtonsoft.Json.dll
-/Users/williamcheng/Code/swagger-codegen/samples/client/petstore/csharp/SwaggerClientTest/bin/Debug/nunit.framework.dll
-/Users/williamcheng/Code/swagger-codegen/samples/client/petstore/csharp/SwaggerClientTest/bin/Debug/RestSharp.dll
-/Users/williamcheng/Code/swagger-codegen/samples/client/petstore/csharp/SwaggerClientTest/bin/Debug/SwaggerClientTest.dll.mdb
-/Users/williamcheng/Code/swagger-codegen/samples/client/petstore/csharp/SwaggerClientTest/bin/Debug/SwaggerClientTest.dll
-/Users/williamcheng/Code/swagger-codegen/samples/client/petstore/csharp/SwaggerClientTest/obj/Debug/SwaggerClientTest.dll
-/Users/williamcheng/Code/swagger-codegen/samples/client/petstore/csharp/SwaggerClientTest/obj/Debug/SwaggerClientTest.dll.mdb
+/Users/williamcheng/Code/csharp/swagger-codegen/samples/client/petstore/csharp/SwaggerClientTest/obj/Debug/.NETFramework,Version=v4.5.AssemblyAttribute.cs
+/Users/williamcheng/Code/csharp/swagger-codegen/samples/client/petstore/csharp/SwaggerClientTest/bin/Debug/SwaggerClientTest.dll.mdb
+/Users/williamcheng/Code/csharp/swagger-codegen/samples/client/petstore/csharp/SwaggerClientTest/bin/Debug/SwaggerClientTest.dll
+/Users/williamcheng/Code/csharp/swagger-codegen/samples/client/petstore/csharp/SwaggerClientTest/obj/Debug/SwaggerClientTest.dll
+/Users/williamcheng/Code/csharp/swagger-codegen/samples/client/petstore/csharp/SwaggerClientTest/obj/Debug/SwaggerClientTest.dll.mdb
+/Users/williamcheng/Code/csharp/swagger-codegen/samples/client/petstore/csharp/SwaggerClientTest/bin/Debug/Newtonsoft.Json.dll
+/Users/williamcheng/Code/csharp/swagger-codegen/samples/client/petstore/csharp/SwaggerClientTest/bin/Debug/nunit.framework.dll
+/Users/williamcheng/Code/csharp/swagger-codegen/samples/client/petstore/csharp/SwaggerClientTest/bin/Debug/RestSharp.dll
diff --git a/samples/client/petstore/csharp/SwaggerClientTest/obj/Debug/SwaggerClientTest.dll b/samples/client/petstore/csharp/SwaggerClientTest/obj/Debug/SwaggerClientTest.dll
index c292bea9bad..c975e54d4be 100755
Binary files a/samples/client/petstore/csharp/SwaggerClientTest/obj/Debug/SwaggerClientTest.dll and b/samples/client/petstore/csharp/SwaggerClientTest/obj/Debug/SwaggerClientTest.dll differ
diff --git a/samples/client/petstore/csharp/SwaggerClientTest/obj/Debug/SwaggerClientTest.dll.mdb b/samples/client/petstore/csharp/SwaggerClientTest/obj/Debug/SwaggerClientTest.dll.mdb
index f63c1d21fe3..5c1092d07fc 100644
Binary files a/samples/client/petstore/csharp/SwaggerClientTest/obj/Debug/SwaggerClientTest.dll.mdb and b/samples/client/petstore/csharp/SwaggerClientTest/obj/Debug/SwaggerClientTest.dll.mdb differ