diff --git a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/CSharpClientCodegen.java b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/CSharpClientCodegen.java
index c898ee4ebe5..f473257d9cf 100644
--- a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/CSharpClientCodegen.java
+++ b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/CSharpClientCodegen.java
@@ -48,6 +48,7 @@ public class CSharpClientCodegen extends AbstractCSharpCodegen {
     protected String targetFrameworkNuget = "net45";
     protected boolean supportsAsync = Boolean.TRUE;
     protected boolean supportsUWP = Boolean.FALSE;
+    protected Map<Character, String> regexModifiers;
 
 
     protected final Map<String, String> frameworks;
@@ -127,6 +128,12 @@ public class CSharpClientCodegen extends AbstractCSharpCodegen {
         addSwitch(CodegenConstants.OPTIONAL_EMIT_DEFAULT_VALUES,
                 CodegenConstants.OPTIONAL_EMIT_DEFAULT_VALUES_DESC,
                 this.optionalEmitDefaultValue);
+
+        regexModifiers = new HashMap<Character, String>();
+        regexModifiers.put('i', "IgnoreCase");
+        regexModifiers.put('m', "Multiline");
+        regexModifiers.put('s', "Singleline");
+        regexModifiers.put('x', "IgnorePatternWhitespace");
     }
 
     @Override
@@ -333,6 +340,56 @@ public class CSharpClientCodegen extends AbstractCSharpCodegen {
     	return super.postProcessModels(objMap);
     }
 
+    @Override
+    public void postProcessParameter(CodegenParameter parameter) {
+        postProcessPattern(parameter.pattern, parameter.vendorExtensions);
+        super.postProcessParameter(parameter);
+    }
+
+    @Override
+    public void postProcessModelProperty(CodegenModel model, CodegenProperty property) {
+        postProcessPattern(property.pattern, property.vendorExtensions);
+        super.postProcessModelProperty(model, property);
+    }
+
+
+    /*
+    * The swagger pattern spec follows the Perl convention and style of modifiers. .NET
+    * does not support this syntax directly so we need to convert the pattern to a .NET compatible
+    * format and apply modifiers in a compatible way.
+    * See https://msdn.microsoft.com/en-us/library/yd1hzczs(v=vs.110).aspx for .NET options.
+    * See https://github.com/swagger-api/swagger-codegen/pull/2794 for Python's initial implementation from which this is copied.
+    */
+    public void postProcessPattern(String pattern, Map<String, Object> vendorExtensions) {
+        if(pattern != null) {
+            int i = pattern.lastIndexOf('/');
+
+            //Must follow Perl /pattern/modifiers convention
+            if(pattern.charAt(0) != '/' || i < 2) {
+                throw new IllegalArgumentException("Pattern must follow the Perl "
+                        + "/pattern/modifiers convention. "+pattern+" is not valid.");
+            }
+
+            String regex = pattern.substring(1, i).replace("'", "\'");
+            List<String> modifiers = new ArrayList<String>();
+
+            // perl requires an explicit modifier to be culture specific and .NET is the reverse.
+            modifiers.add("CultureInvariant");
+
+            for(char c : pattern.substring(i).toCharArray()) {
+                if(regexModifiers.containsKey(c)) {
+                    String modifier = regexModifiers.get(c);
+                    modifiers.add(modifier);
+                } else if (c == 'l') {
+                    modifiers.remove("CultureInvariant");
+                }
+            }
+
+            vendorExtensions.put("x-regex", regex);
+            vendorExtensions.put("x-modifiers", modifiers);
+        }
+    }
+
     public void setTargetFramework(String dotnetFramework) {
         if(!frameworks.containsKey(dotnetFramework)){
             LOGGER.warn("Invalid .NET framework version, defaulting to " + this.targetFramework);
diff --git a/modules/swagger-codegen/src/main/resources/csharp/Project.mustache b/modules/swagger-codegen/src/main/resources/csharp/Project.mustache
index 2334e53d0c9..a2698233a3a 100644
--- a/modules/swagger-codegen/src/main/resources/csharp/Project.mustache
+++ b/modules/swagger-codegen/src/main/resources/csharp/Project.mustache
@@ -66,6 +66,7 @@ limitations under the License.
     <Reference Include="System.Core" />
     <Reference Include="System.Xml.Linq" />
     <Reference Include="System.Data.DataSetExtensions" />
+    <Reference Include="System.ComponentModel.DataAnnotations" />
     <Reference Include="Microsoft.CSharp" />
     <Reference Include="System.Data" />
     <Reference Include="System.Runtime.Serialization" />
diff --git a/modules/swagger-codegen/src/main/resources/csharp/TestProject.mustache b/modules/swagger-codegen/src/main/resources/csharp/TestProject.mustache
index 07448f9cfef..e08b2429864 100644
--- a/modules/swagger-codegen/src/main/resources/csharp/TestProject.mustache
+++ b/modules/swagger-codegen/src/main/resources/csharp/TestProject.mustache
@@ -66,6 +66,7 @@ limitations under the License.
     <Reference Include="System.Core" />
     <Reference Include="System.Xml.Linq" />
     <Reference Include="System.Data.DataSetExtensions" />
+    <Reference Include="System.ComponentModel.DataAnnotations" />
     <Reference Include="Microsoft.CSharp" />
     <Reference Include="System.Data" />
     <Reference Include="System.Runtime.Serialization" />
diff --git a/modules/swagger-codegen/src/main/resources/csharp/model.mustache b/modules/swagger-codegen/src/main/resources/csharp/model.mustache
index 863d7ba93ef..6d53e0f84e1 100644
--- a/modules/swagger-codegen/src/main/resources/csharp/model.mustache
+++ b/modules/swagger-codegen/src/main/resources/csharp/model.mustache
@@ -3,12 +3,14 @@ using System;
 using System.Linq;
 using System.IO;
 using System.Text;
+using System.Text.RegularExpressions;
 using System.Collections;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Runtime.Serialization;
 using Newtonsoft.Json;
 using Newtonsoft.Json.Converters;
+using System.ComponentModel.DataAnnotations;
 
 {{#models}}
 {{#model}}
diff --git a/modules/swagger-codegen/src/main/resources/csharp/modelGeneric.mustache b/modules/swagger-codegen/src/main/resources/csharp/modelGeneric.mustache
index aaf6df8cf2e..2581a723763 100644
--- a/modules/swagger-codegen/src/main/resources/csharp/modelGeneric.mustache
+++ b/modules/swagger-codegen/src/main/resources/csharp/modelGeneric.mustache
@@ -2,7 +2,7 @@
     /// {{#description}}{{.}}{{/description}}{{^description}}{{classname}}{{/description}}
     /// </summary>
     [DataContract]
-    public partial class {{classname}} : {{#parent}}{{{parent}}}, {{/parent}} IEquatable<{{classname}}>
+    public partial class {{classname}} : {{#parent}}{{{parent}}}, {{/parent}} IEquatable<{{classname}}>, IValidatableObject
     {
         {{#vars}}
         {{#isEnum}}
@@ -169,4 +169,39 @@ this.{{name}} = {{name}};
                 return hash;
             }
         }
+        public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
+        { {{#vars}}{{#hasValidation}}{{#maxLength}}
+            // {{{name}}} ({{{datatype}}}) maxLength
+            if(this.{{{name}}} != null && this.{{{name}}}.Length > {{maxLength}})
+            {
+                yield return new ValidationResult("Invalid value for {{{name}}}, length must be less than {{maxLength}}.", new [] { "{{{name}}}" });
+            }
+{{/maxLength}}{{#minLength}}
+            // {{{name}}} ({{{datatype}}}) minLength
+            if(this.{{{name}}} != null && this.{{{name}}}.Length < {{minLength}})
+            {
+                yield return new ValidationResult("Invalid value for {{{name}}}, length must be greater than {{minLength}}.", new [] { "{{{name}}}" });
+            }
+{{/minLength}}{{#maximum}}
+            // {{{name}}} ({{{datatype}}}) maximum
+            if(this.{{{name}}} > ({{{datatype}}}){{maximum}})
+            {
+                yield return new ValidationResult("Invalid value for {{{name}}}, must be a value less than or equal to {{maximum}}.", new [] { "{{{name}}}" });
+            }
+{{/maximum}}{{#minimum}}
+            // {{{name}}} ({{{datatype}}}) minimum
+            if(this.{{{name}}} < ({{{datatype}}}){{minimum}})
+            {
+                yield return new ValidationResult("Invalid value for {{{name}}}, must be a value greater than or equal to {{minimum}}.", new [] { "{{{name}}}" });
+            }
+{{/minimum}}{{#pattern}}
+            // {{{name}}} ({{{datatype}}}) pattern
+            Regex regex{{{name}}} = new Regex(@"{{vendorExtensions.x-regex}}"{{#vendorExtensions.x-modifiers}}{{#-first}}, {{/-first}}RegexOptions.{{.}}{{^-last}} | {{/-last}}{{/vendorExtensions.x-modifiers}});
+            if (false == regex{{{name}}}.Match(this.{{{name}}}).Success)
+            {
+                yield return new ValidationResult("Invalid value for {{{name}}}, must match a pattern of {{pattern}}.", new [] { "{{{name}}}" });
+            }
+{{/pattern}}{{/hasValidation}}{{/vars}}
+            yield break;
+        }
     }