Implement validation for extra properties of the extensible objects

docs/en/Object-Extensions.md

@@ -156,25 +156,123 @@ ObjectExtensionManager.Instance
     );
 ````
 
-#### Property Configuration
+### Property Configuration
 
-`AddOrUpdateProperty` can also get an action that can perform additional configuration on the property definition.
-
-Example:
+`AddOrUpdateProperty` can also get an action that can perform additional configuration on the property definition:
 
 ````csharp
 ObjectExtensionManager.Instance
     .AddOrUpdateProperty<IdentityUser, string>(
         "SocialSecurityNumber",
         options =>
         {
-            options.CheckPairDefinitionOnMapping = false;
+            //Configure options...
+        });
+````
+
+> `options` has a dictionary, named `Configuration` which makes the object extension definitions even extensible. It is used by the EF Core to map extra properties to table fields in the database. See the [extending entities](Customizing-Application-Modules-Extending-Entities.md) document.
+
+The following sections explain the fundamental property configuration options.
+
+#### CheckPairDefinitionOnMapping
+
+Controls how to check property definitions while mapping two extensible objects. See the "Object to Object Mapping" section to understand the `CheckPairDefinitionOnMapping` option better.
+
+## Validation
+
+You may want to add some **validation rules** for the extra properties you've defined. `AddOrUpdateProperty` method options allows two ways of performing validation:
+
+1. You can add **data annotation attributes** for a property.
+2. You can write an action (code block) to perform a **custom validation**.
+
+Validation works when you use the object in a method that is **automatically validated** (e.g. controller actions, page handler methods, application service methods...). So, all extra properties are validated whenever the extended object is being validated.
+
+### Data Annotation Attributes
+
+All of the standard data annotation attributes are valid for extra properties. Example:
+
+````csharp
+ObjectExtensionManager.Instance
+    .AddOrUpdateProperty<IdentityUserCreateDto, string>(
+        "SocialSecurityNumber",
+        options =>
+        {
+            options.ValidationAttributes.Add(new RequiredAttribute());
+            options.ValidationAttributes.Add(
+                new StringLengthAttribute(32) {
+                    MinimumLength = 6 
+                }
+            );
+        });
+````
+
+With this configuration, `IdentityUserCreateDto` objects will be invalid without a valid `SocialSecurityNumber` value provided.
+
+### Custom Validation
+
+If you need, you can add a custom action that is executed to validate the extra properties. Example:
+
+````csharp
+ObjectExtensionManager.Instance
+    .AddOrUpdateProperty<IdentityUserCreateDto, string>(
+        "SocialSecurityNumber",
+        options =>
+        {
+            options.Validators.Add(context =>
+            {
+                var socialSecurityNumber = context.Value as string;
+
+                if (socialSecurityNumber == null ||
+                    socialSecurityNumber.StartsWith("X"))
+                {
+                    context.ValidationErrors.Add(
+                        new ValidationResult(
+                            "Invalid social security number: " + socialSecurityNumber,
+                            new[] { "SocialSecurityNumber" }
+                        )
+                    );
+                }
+            });
         });
 ````
 
-> See the "Object to Object Mapping" section to understand the `CheckPairDefinitionOnMapping` option.
+`context.ServiceProvider` can be used to resolve a service dependency for advanced scenarios.
+
+In addition to add custom validation logic for a single property, you can add a custom validation logic that is executed in object level. Example:
 
-`options` has a dictionary, named `Configuration` which makes the object extension definitions even extensible. It is used by the EF Core to map extra properties to table fields in the database. See the [extending entities](Customizing-Application-Modules-Extending-Entities.md) document.
+````csharp
+ObjectExtensionManager.Instance
+.AddOrUpdate<IdentityUserCreateDto>(objConfig =>
+{
+    //Define two properties with their own validation rules
+
+    objConfig.AddOrUpdateProperty<string>("Password", propertyConfig =>
+    {
+        propertyConfig.ValidationAttributes.Add(new RequiredAttribute());
+    });
+
+    objConfig.AddOrUpdateProperty<string>("PasswordRepeat", propertyConfig =>
+    {
+        propertyConfig.ValidationAttributes.Add(new RequiredAttribute());
+    });
+
+    //Write a common validation logic works on multiple properties
+
+    objConfig.Validators.Add(context =>
+    {
+        if (context.ValidatingObject.GetProperty<string>("Password") !=
+            context.ValidatingObject.GetProperty<string>("PasswordRepeat"))
+        {
+            context.ValidationErrors.Add(
+                new ValidationResult(
+                    "Please repeat the same password!",
+                    new[] { "Password", "PasswordRepeat" }
+                )
+            );
+        }
+    });
+});
+````
 
 ## Object to Object Mapping
 

framework/src/Volo.Abp.Ddd.Domain/Volo/Abp/Domain/Entities/AggregateRoot.cs

@@ -1,8 +1,10 @@
 using System;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
+using System.ComponentModel.DataAnnotations;
 using Volo.Abp.Auditing;
 using Volo.Abp.Data;
+using Volo.Abp.ObjectExtending;
 
 namespace Volo.Abp.Domain.Entities
 {
@@ -56,6 +58,14 @@ public virtual void ClearDistributedEvents()
         {
             _distributedEvents.Clear();
         }
+
+        public virtual IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
+        {
+            return ExtensibleObjectValidator.GetValidationErrors(
+                this,
+                validationContext
+            );
+        }
     }
 
     [Serializable]
@@ -115,5 +125,13 @@ public virtual void ClearDistributedEvents()
         {
             _distributedEvents.Clear();
         }
+
+        public virtual IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
+        {
+            return ExtensibleObjectValidator.GetValidationErrors(
+                this,
+                validationContext
+            );
+        }
     }
 }

framework/src/Volo.Abp.ObjectExtending/Volo/Abp/Data/HasExtraPropertiesExtensions.cs

@@ -5,24 +5,27 @@
 
 namespace Volo.Abp.Data
 {
+    //TODO: Move to Volo.Abp.Data.ObjectExtending namespace at v3.0
+
     public static class HasExtraPropertiesExtensions
     {
         public static bool HasProperty(this IHasExtraProperties source, string name)
         {
             return source.ExtraProperties.ContainsKey(name);
         }
 
-        public static object GetProperty(this IHasExtraProperties source, string name)
+        public static object GetProperty(this IHasExtraProperties source, string name, object defaultValue = null)
         {
-            return source.ExtraProperties?.GetOrDefault(name);
+            return source.ExtraProperties?.GetOrDefault(name)
+                   ?? defaultValue;
         }
 
-        public static TProperty GetProperty<TProperty>(this IHasExtraProperties source, string name)
+        public static TProperty GetProperty<TProperty>(this IHasExtraProperties source, string name, TProperty defaultValue = default)
         {
             var value = source.GetProperty(name);
-            if (value == default)
+            if (value == null)
             {
-                return default;
+                return defaultValue;
             }
 
             if (TypeHelper.IsPrimitiveExtended(typeof(TProperty), includeEnums: true))

framework/src/Volo.Abp.ObjectExtending/Volo/Abp/Data/IHasExtraProperties.cs

@@ -2,6 +2,8 @@
 
 namespace Volo.Abp.Data
 {
+    //TODO: Move to Volo.Abp.Data.ObjectExtending namespace at v3.0
+
     public interface IHasExtraProperties
     {
         Dictionary<string, object> ExtraProperties { get; }

framework/src/Volo.Abp.ObjectExtending/Volo/Abp/ObjectExtending/ExtensibleObject.cs

@@ -1,17 +1,26 @@
 using System;
 using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
 using Volo.Abp.Data;
 
 namespace Volo.Abp.ObjectExtending
 {
     [Serializable]
-    public class ExtensibleObject : IHasExtraProperties
+    public class ExtensibleObject : IHasExtraProperties, IValidatableObject
     {
         public Dictionary<string, object> ExtraProperties { get; protected set; }
 
         public ExtensibleObject()
         {
             ExtraProperties = new Dictionary<string, object>();
         }
+
+        public virtual IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
+        {
+            return ExtensibleObjectValidator.GetValidationErrors(
+                this,
+                validationContext
+            );
+        }
     }
 }