Imported Upstream version 4.0.0~alpha1

Former-commit-id: 806294f5ded97629b74c85c09952f2a74fe182d9

external/referencesource/System.Web/ModelBinding/ValidatableObjectAdapter.cs

@@ -0,0 +1,53 @@
+namespace System.Web.ModelBinding {
+    using System;
+    using System.Collections.Generic;
+    using System.ComponentModel.DataAnnotations;
+    using System.Globalization;
+    using System.Linq;
+
+    public class ValidatableObjectAdapter : ModelValidator {
+        public ValidatableObjectAdapter(ModelMetadata metadata, ModelBindingExecutionContext context)
+            : base(metadata, context) {
+        }
+
+        public override IEnumerable<ModelValidationResult> Validate(object container) {
+            // NOTE: Container is never used here, because IValidatableObject doesn't give you
+            // any way to get access to your container.
+
+            object model = Metadata.Model;
+            if (model == null) {
+                return Enumerable.Empty<ModelValidationResult>();
+            }
+
+            IValidatableObject validatable = model as IValidatableObject;
+            if (validatable == null) {
+                throw new InvalidOperationException(
+                    String.Format(
+                        CultureInfo.CurrentCulture,
+                        SR.GetString(SR.ValidatableObjectAdapter_IncompatibleType),
+                        typeof(IValidatableObject).FullName,
+                        model.GetType().FullName
+                    )
+                );
+            }
+
+            ValidationContext validationContext = new ValidationContext(validatable, null, null);
+            return ConvertResults(validatable.Validate(validationContext));
+        }
+
+        private IEnumerable<ModelValidationResult> ConvertResults(IEnumerable<ValidationResult> results) {
+            foreach (ValidationResult result in results) {
+                if (result != ValidationResult.Success) {
+                    if (result.MemberNames == null || !result.MemberNames.Any()) {
+                        yield return new ModelValidationResult { Message = result.ErrorMessage };
+                    }
+                    else {
+                        foreach (string memberName in result.MemberNames) {
+                            yield return new ModelValidationResult { Message = result.ErrorMessage, MemberName = memberName };
+                        }
+                    }
+                }
+            }
+        }
+    }
+}