From 959e7027b07b6c242f98438b901dc9a57904b097 Mon Sep 17 00:00:00 2001
From: Jeremy Skinner <jeremy@jeremyskinner.co.uk>
Date: Tue, 21 Nov 2017 19:40:25 +0000
Subject: [PATCH] Add ValidateComplexTypesIfChildValidationFails to
 ValidationVisitor - Allows more granular control of when model-level
 validation should run.

Addresses #7014
---
 .../ModelBinding/Validation/ValidationVisitor.cs          | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/Microsoft.AspNetCore.Mvc.Core/ModelBinding/Validation/ValidationVisitor.cs b/src/Microsoft.AspNetCore.Mvc.Core/ModelBinding/Validation/ValidationVisitor.cs
index 4e721c5731..494a798537 100644
--- a/src/Microsoft.AspNetCore.Mvc.Core/ModelBinding/Validation/ValidationVisitor.cs
+++ b/src/Microsoft.AspNetCore.Mvc.Core/ModelBinding/Validation/ValidationVisitor.cs
@@ -29,6 +29,11 @@ namespace Microsoft.AspNetCore.Mvc.ModelBinding.Validation
         private ModelMetadata _metadata;
         private IValidationStrategy _strategy;
 
+        /// <summary>
+        /// Indicates whether validation of a complex type should be performed if validation fails for any of its children. The default behavior is false. 
+        /// </summary>
+        public bool ValidateComplexTypesIfChildValidationFails { get; set; }
+
         /// <summary>
         /// Creates a new <see cref="ValidationVisitor"/>.
         /// </summary>
@@ -236,7 +241,8 @@ namespace Microsoft.AspNetCore.Mvc.ModelBinding.Validation
             }
 
             // Double-checking HasReachedMaxErrors just in case this model has no properties.
-            if (isValid && !_modelState.HasReachedMaxErrors)
+            // If validation has failed for any children, only validate the parent if ValidateComplexTypesIfChildValidationFails is true.
+            if ((isValid || ValidateComplexTypesIfChildValidationFails) && !_modelState.HasReachedMaxErrors)
             {
                 isValid &= ValidateNode();
             }