Extended types binding support

lib/ApiMultipartFormDataFormatter/Services/Implementations/BaseMultiPartFormdataModelBinderService.cs

@@ -1,5 +1,5 @@
 using System;
-using System.Collections.Generic;
+using System.Linq;
 using System.Reflection;
 using ApiMultiPartFormData.Services.Interfaces;
 
@@ -23,14 +23,46 @@ public object BuildModel(PropertyInfo propertyInfo, object value)
 
             // Get property type.
             var propertyType = propertyInfo.PropertyType;
+            var underlyingType = Nullable.GetUnderlyingType(propertyType);
 
             // Property is GUID.
             if (propertyType == typeof(Guid) && Guid.TryParse(value.ToString(), out var guid))
                 return guid;
+            if (underlyingType == typeof(Guid))
+            {
+                if (Guid.TryParse(value.ToString(), out guid))
+                    return guid;
+                return null;
+            }
+
+            // Property is Enum.
+            if (propertyType.IsEnum)
+                return convertToEnum(propertyType, value.ToString());
+            if (underlyingType != null && underlyingType.IsEnum)
+            {
+                if (string.IsNullOrWhiteSpace(value.ToString()))
+                    return null;
+                return convertToEnum(underlyingType, value.ToString());
+            }
+
+            // Other Nullable types
+            if (underlyingType != null)
+            {
+                if (string.IsNullOrEmpty(value.ToString())) return null;
+                propertyType = underlyingType;
+            }
 
             return Convert.ChangeType(value, propertyType);
         }
 
+        object convertToEnum(Type type, string val)
+        {
+            if (int.TryParse(val, out var num))
+                return Enum.ToObject(type, num);
+
+            return Enum.Parse(type, val, true);
+        }
+
         #endregion
     }
 }