diff --git a/modules/swagger-codegen/src/main/resources/aspnet5/model.mustache b/modules/swagger-codegen/src/main/resources/aspnet5/model.mustache
index bb4e7af9d76..08aaed01f3d 100644
--- a/modules/swagger-codegen/src/main/resources/aspnet5/model.mustache
+++ b/modules/swagger-codegen/src/main/resources/aspnet5/model.mustache
@@ -20,10 +20,30 @@ namespace {{packageName}}.Models
         /// <summary>
         /// Initializes a new instance of the <see cref="{{classname}}" /> class.
         /// </summary>
-        public {{classname}}()
+{{#vars}}        /// <param name="{{name}}">{{#description}}{{description}}{{/description}}{{^description}}{{name}}{{/description}}{{#required}} (required){{/required}}{{#defaultValue}} (default to {{defaultValue}}){{/defaultValue}}.</param>
+{{/vars}}
+        public {{classname}}({{#vars}}{{{datatype}}} {{name}} = null{{#hasMore}}, {{/hasMore}}{{/vars}})
         {
-            {{#vars}}{{#defaultValue}}this.{{name}} = {{{defaultValue}}};
-            {{/defaultValue}}{{/vars}}
+            {{#vars}}{{#required}}// to ensure "{{name}}" is required (not null)
+            if ({{name}} == null)
+            {
+                throw new InvalidDataException("{{name}} is a required property for {{classname}} and cannot be null");
+            }
+            else
+            {
+                this.{{name}} = {{name}};
+            }
+            {{/required}}{{/vars}}{{#vars}}{{^required}}{{#defaultValue}}// use default value if no "{{name}}" provided
+            if ({{name}} == null)
+            {
+                this.{{name}} = {{{defaultValue}}};
+            }
+            else
+            {
+                this.{{name}} = {{name}};
+            }
+            {{/defaultValue}}{{^defaultValue}}this.{{name}} = {{name}};
+            {{/defaultValue}}{{/required}}{{/vars}}
         }
 
         {{#vars}}
diff --git a/samples/server/petstore/aspnet5/src/IO.Swagger/Models/Category.cs b/samples/server/petstore/aspnet5/src/IO.Swagger/Models/Category.cs
index 0ae013fb688..1bdccbdc4e1 100644
--- a/samples/server/petstore/aspnet5/src/IO.Swagger/Models/Category.cs
+++ b/samples/server/petstore/aspnet5/src/IO.Swagger/Models/Category.cs
@@ -18,8 +18,12 @@ namespace IO.Swagger.Models
         /// <summary>
         /// Initializes a new instance of the <see cref="Category" /> class.
         /// </summary>
-        public Category()
+        /// <param name="Id">Id.</param>
+        /// <param name="Name">Name.</param>
+        public Category(long? Id = null, string Name = null)
         {
+            this.Id = Id;
+            this.Name = Name;
             
         }
 
diff --git a/samples/server/petstore/aspnet5/src/IO.Swagger/Models/Order.cs b/samples/server/petstore/aspnet5/src/IO.Swagger/Models/Order.cs
index e8bd7610bb6..27252258328 100644
--- a/samples/server/petstore/aspnet5/src/IO.Swagger/Models/Order.cs
+++ b/samples/server/petstore/aspnet5/src/IO.Swagger/Models/Order.cs
@@ -18,8 +18,20 @@ namespace IO.Swagger.Models
         /// <summary>
         /// Initializes a new instance of the <see cref="Order" /> class.
         /// </summary>
-        public Order()
+        /// <param name="Id">Id.</param>
+        /// <param name="PetId">PetId.</param>
+        /// <param name="Quantity">Quantity.</param>
+        /// <param name="ShipDate">ShipDate.</param>
+        /// <param name="Status">Order Status.</param>
+        /// <param name="Complete">Complete.</param>
+        public Order(long? Id = null, long? PetId = null, int? Quantity = null, DateTime? ShipDate = null, string Status = null, bool? Complete = null)
         {
+            this.Id = Id;
+            this.PetId = PetId;
+            this.Quantity = Quantity;
+            this.ShipDate = ShipDate;
+            this.Status = Status;
+            this.Complete = Complete;
             
         }
 
diff --git a/samples/server/petstore/aspnet5/src/IO.Swagger/Models/Pet.cs b/samples/server/petstore/aspnet5/src/IO.Swagger/Models/Pet.cs
index 5cf91ebe054..e2756f6a80d 100644
--- a/samples/server/petstore/aspnet5/src/IO.Swagger/Models/Pet.cs
+++ b/samples/server/petstore/aspnet5/src/IO.Swagger/Models/Pet.cs
@@ -18,8 +18,36 @@ namespace IO.Swagger.Models
         /// <summary>
         /// Initializes a new instance of the <see cref="Pet" /> class.
         /// </summary>
-        public Pet()
+        /// <param name="Id">Id.</param>
+        /// <param name="Category">Category.</param>
+        /// <param name="Name">Name (required).</param>
+        /// <param name="PhotoUrls">PhotoUrls (required).</param>
+        /// <param name="Tags">Tags.</param>
+        /// <param name="Status">pet status in the store.</param>
+        public Pet(long? Id = null, Category Category = null, string Name = null, List<string> PhotoUrls = null, List<Tag> Tags = null, string Status = null)
         {
+            // to ensure "Name" is required (not null)
+            if (Name == null)
+            {
+                throw new InvalidDataException("Name is a required property for Pet and cannot be null");
+            }
+            else
+            {
+                this.Name = Name;
+            }
+            // to ensure "PhotoUrls" is required (not null)
+            if (PhotoUrls == null)
+            {
+                throw new InvalidDataException("PhotoUrls is a required property for Pet and cannot be null");
+            }
+            else
+            {
+                this.PhotoUrls = PhotoUrls;
+            }
+            this.Id = Id;
+            this.Category = Category;
+            this.Tags = Tags;
+            this.Status = Status;
             
         }
 
diff --git a/samples/server/petstore/aspnet5/src/IO.Swagger/Models/Tag.cs b/samples/server/petstore/aspnet5/src/IO.Swagger/Models/Tag.cs
index 159e65015f4..ce8a4e8eafe 100644
--- a/samples/server/petstore/aspnet5/src/IO.Swagger/Models/Tag.cs
+++ b/samples/server/petstore/aspnet5/src/IO.Swagger/Models/Tag.cs
@@ -18,8 +18,12 @@ namespace IO.Swagger.Models
         /// <summary>
         /// Initializes a new instance of the <see cref="Tag" /> class.
         /// </summary>
-        public Tag()
+        /// <param name="Id">Id.</param>
+        /// <param name="Name">Name.</param>
+        public Tag(long? Id = null, string Name = null)
         {
+            this.Id = Id;
+            this.Name = Name;
             
         }
 
diff --git a/samples/server/petstore/aspnet5/src/IO.Swagger/Models/User.cs b/samples/server/petstore/aspnet5/src/IO.Swagger/Models/User.cs
index c20ef235807..9c3737b8b32 100644
--- a/samples/server/petstore/aspnet5/src/IO.Swagger/Models/User.cs
+++ b/samples/server/petstore/aspnet5/src/IO.Swagger/Models/User.cs
@@ -18,8 +18,24 @@ namespace IO.Swagger.Models
         /// <summary>
         /// Initializes a new instance of the <see cref="User" /> class.
         /// </summary>
-        public User()
+        /// <param name="Id">Id.</param>
+        /// <param name="Username">Username.</param>
+        /// <param name="FirstName">FirstName.</param>
+        /// <param name="LastName">LastName.</param>
+        /// <param name="Email">Email.</param>
+        /// <param name="Password">Password.</param>
+        /// <param name="Phone">Phone.</param>
+        /// <param name="UserStatus">User Status.</param>
+        public User(long? Id = null, string Username = null, string FirstName = null, string LastName = null, string Email = null, string Password = null, string Phone = null, int? UserStatus = null)
         {
+            this.Id = Id;
+            this.Username = Username;
+            this.FirstName = FirstName;
+            this.LastName = LastName;
+            this.Email = Email;
+            this.Password = Password;
+            this.Phone = Phone;
+            this.UserStatus = UserStatus;
             
         }