Refactored Validation package code on code review session.

src/Volo.Abp.Validation/Volo/Abp/Validation/DataAnnotationValidator.cs

@@ -10,53 +10,61 @@ namespace Volo.Abp.Validation
     {
         public void Validate(object validatingObject)
         {
-            var validationResult = new AbpValidationResult();
+            var errors = GetErrors(validatingObject);
 
-            AddErrors(validationResult, validatingObject);
-
-            if (validationResult.Errors.Any())
+            if (errors.Any())
             {
                 throw new AbpValidationException(
                     "Object state is not valid! See ValidationErrors for details.",
-                    validationResult.Errors
+                    errors
                 );
             }
         }
 
         /// <summary>
-        /// Checks all properties for DataAnnotations attributes.
+        /// Gets all errors from properties for DataAnnotations attributes and IValidatableObject interface.
         /// </summary>
-        public virtual void AddErrors(IAbpValidationResult validationResult, object validatingObject)
+        public virtual List<ValidationResult> GetErrors(object validatingObject)
         {
+            var errors = new List<ValidationResult>();
             var properties = TypeDescriptor.GetProperties(validatingObject).Cast<PropertyDescriptor>();
+
             foreach (var property in properties)
             {
-                var validationAttributes = property.Attributes.OfType<ValidationAttribute>().ToArray();
-                if (validationAttributes.IsNullOrEmpty())
-                {
-                    continue;
-                }
+                AddPropertyErrors(validatingObject, property, errors);
+            }
 
-                var validationContext = new ValidationContext(validatingObject)
-                {
-                    DisplayName = property.DisplayName,
-                    MemberName = property.Name
-                };
+            if (validatingObject is IValidatableObject validatableObject)
+            {
+                errors.AddRange(
+                    validatableObject.Validate(new ValidationContext(validatableObject))
+                );
+            }
 
-                foreach (var attribute in validationAttributes)
-                {
-                    var result = attribute.GetValidationResult(property.GetValue(validatingObject), validationContext);
-                    if (result != null)
-                    {
-                        validationResult.Errors.Add(result);
-                    }
-                }
+            return errors;
+        }
+
+        protected virtual void AddPropertyErrors(object validatingObject, PropertyDescriptor property, List<ValidationResult> errors)
+        {
+            var validationAttributes = property.Attributes.OfType<ValidationAttribute>().ToArray();
+            if (validationAttributes.IsNullOrEmpty())
+            {
+                return;
             }
 
-            if (validatingObject is IValidatableObject)
+            var validationContext = new ValidationContext(validatingObject)
             {
-                var results = (validatingObject as IValidatableObject).Validate(new ValidationContext(validatingObject));
-                validationResult.Errors.AddRange(results);
+                DisplayName = property.DisplayName,
+                MemberName = property.Name
+            };
+
+            foreach (var attribute in validationAttributes)
+            {
+                var result = attribute.GetValidationResult(property.GetValue(validatingObject), validationContext);
+                if (result != null)
+                {
+                    errors.Add(result);
+                }
             }
         }
     }

src/Volo.Abp.Validation/Volo/Abp/Validation/IDataAnnotationValidator.cs

@@ -1,9 +1,12 @@
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
+
 namespace Volo.Abp.Validation
 {
     public interface IDataAnnotationValidator
     {
         void Validate(object validatingObject);
 
-        void AddErrors(IAbpValidationResult validationResult, object validatingObject);
+        List<ValidationResult> GetErrors(object validatingObject);
     }
 }

src/Volo.Abp.Validation/Volo/Abp/Validation/IObjectValidator.cs

@@ -1,9 +1,16 @@
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
+
 namespace Volo.Abp.Validation
 {
     public interface IObjectValidator
     {
-        void Validate(object validatingObject, string name = null, bool allowNull = false);
+        void Validate(
+            object validatingObject,
+            string name = null,
+            bool allowNull = false
+        );
 
-        void AddErrors(IAbpValidationResult validationResult, object validatingObject, string name = null, bool allowNull = false);
+        List<ValidationResult> GetErrors(object validatingObject, string name = null, bool allowNull = false);
     }
 }

src/Volo.Abp.Validation/Volo/Abp/Validation/MethodInvocationValidator.cs

@@ -40,6 +40,7 @@ namespace Volo.Abp.Validation
                 throw new Exception("Method parameter count does not match with argument count!");
             }
 
+            //todo: consider to remove this condition
             if (context.Errors.Any() && HasSingleNullArgument(context))
             {
                 ThrowValidationError(context);
@@ -90,7 +91,7 @@ namespace Volo.Abp.Validation
                              parameterInfo.IsOut ||
                              TypeHelper.IsPrimitiveExtendedIncludingNullable(parameterInfo.ParameterType, includeEnums: true);
 
-            _objectValidator.AddErrors(context, parameterValue, parameterInfo.Name, allowNulls);
+            context.Errors.AddRange(_objectValidator.GetErrors(parameterValue, parameterInfo.Name, allowNulls));
         }
     }
 }

src/Volo.Abp.Validation/Volo/Abp/Validation/ObjectValidator.cs

@@ -1,4 +1,5 @@
 using System.Collections;
+using System.Collections.Generic;
 using System.ComponentModel;
 using System.ComponentModel.DataAnnotations;
 using System.Linq;
@@ -8,7 +9,7 @@ using Volo.Abp.Reflection;
 
 namespace Volo.Abp.Validation
 {
-    public class ObjectValidator : ITransientDependency, IObjectValidator
+    public class ObjectValidator : IObjectValidator, ITransientDependency
     {
         private const int MaxRecursiveParameterValidationDepth = 8;
 
@@ -23,36 +24,38 @@ namespace Volo.Abp.Validation
 
         public virtual void Validate(object validatingObject, string name = null, bool allowNull = false)
         {
-            var validationResult = new AbpValidationResult();
+            var errors = GetErrors(validatingObject, name, allowNull);
 
-            AddErrors(validationResult, validatingObject, name, allowNull);
-
-            if (validationResult.Errors.Any())
+            if (errors.Any())
             {
                 throw new AbpValidationException(
                     "Object state is not valid! See ValidationErrors for details.",
-                    validationResult.Errors
+                    errors
                 );
             }
         }
 
-        public virtual void AddErrors(IAbpValidationResult validationResult, object validatingObject, string name = null, bool allowNull = false)
+        public virtual List<ValidationResult> GetErrors(object validatingObject, string name = null, bool allowNull = false)
         {
+            var errors = new List<ValidationResult>();
+
             if (validatingObject == null && !allowNull)
             {
-                validationResult.Errors.Add(
+                errors.Add(
                     name == null
                         ? new ValidationResult("Given object is null!")
                         : new ValidationResult(name + " is null!", new[] { name })
                 );
 
-                return;
+                return errors;
             }
 
-            ValidateObjectRecursively(validationResult, validatingObject, 1);
+            ValidateObjectRecursively(errors, validatingObject, currentDepth: 1);
+
+            return errors;
         }
 
-        protected virtual void ValidateObjectRecursively(IAbpValidationResult context, object validatingObject, int currentDepth)
+        protected virtual void ValidateObjectRecursively(List<ValidationResult> errors, object validatingObject, int currentDepth)
         {
             if (currentDepth > MaxRecursiveParameterValidationDepth)
             {
@@ -64,20 +67,19 @@ namespace Volo.Abp.Validation
                 return;
             }
 
-            _dataAnnotationValidator.AddErrors(context, validatingObject);
+            errors.AddRange(_dataAnnotationValidator.GetErrors(validatingObject));
 
             //Validate items of enumerable
-            if (validatingObject is IEnumerable && !(validatingObject is IQueryable))
+            if (validatingObject is IEnumerable)
             {
-                foreach (var item in (validatingObject as IEnumerable))
+                if (!(validatingObject is IQueryable))
                 {
-                    ValidateObjectRecursively(context, item, currentDepth + 1);
+                    foreach (var item in (validatingObject as IEnumerable))
+                    {
+                        ValidateObjectRecursively(errors, item, currentDepth + 1);
+                    }
                 }
-            }
 
-            //Do not recursively validate for enumerable objects
-            if (validatingObject is IEnumerable)
-            {
                 return;
             }
 
@@ -102,7 +104,7 @@ namespace Volo.Abp.Validation
                     continue;
                 }
 
-                ValidateObjectRecursively(context, property.GetValue(validatingObject), currentDepth + 1);
+                ValidateObjectRecursively(errors, property.GetValue(validatingObject), currentDepth + 1);
             }
         }
     }