Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.ComponentModel.DataAnnotations/DataAnnotations/CompareAttribute.cs

@@ -0,0 +1,78 @@
+namespace System.ComponentModel.DataAnnotations {
+    using System;
+    using System.Collections.Generic;
+    using System.ComponentModel;
+    using System.ComponentModel.DataAnnotations;
+    using System.ComponentModel.DataAnnotations.Resources;
+    using System.Diagnostics.CodeAnalysis;
+    using System.Globalization;
+    using System.Linq;
+    using System.Reflection;
+
+    [AttributeUsage(AttributeTargets.Property, AllowMultiple = false)]
+    [SuppressMessage("Microsoft.Performance", "CA1813:AvoidUnsealedAttributes", Justification = "This attribute is designed to be a base class for other attributes.")]
+    public class CompareAttribute : ValidationAttribute {
+
+        public CompareAttribute(string otherProperty)
+            : base(DataAnnotationsResources.CompareAttribute_MustMatch) {
+            if (otherProperty == null) {
+                throw new ArgumentNullException("otherProperty");
+            }
+            OtherProperty = otherProperty;
+        }
+
+        public string OtherProperty { get; private set; }
+
+        public string OtherPropertyDisplayName { get; internal set; }
+
+        public override string FormatErrorMessage(string name) {
+            return String.Format(CultureInfo.CurrentCulture, ErrorMessageString, name, OtherPropertyDisplayName ?? OtherProperty);
+        }
+
+        public override bool RequiresValidationContext {
+            get {
+                return true;
+            }
+        }
+
+        protected override ValidationResult IsValid(object value, ValidationContext validationContext) {
+            PropertyInfo otherPropertyInfo = validationContext.ObjectType.GetProperty(OtherProperty);
+            if (otherPropertyInfo == null) {
+                return new ValidationResult(String.Format(CultureInfo.CurrentCulture, DataAnnotationsResources.CompareAttribute_UnknownProperty, OtherProperty));
+            }
+
+            object otherPropertyValue = otherPropertyInfo.GetValue(validationContext.ObjectInstance, null);
+            if (!Equals(value, otherPropertyValue)) {
+                if (OtherPropertyDisplayName == null) {
+                    OtherPropertyDisplayName = GetDisplayNameForProperty(validationContext.ObjectType, OtherProperty);
+                }
+                return new ValidationResult(FormatErrorMessage(validationContext.DisplayName));
+            }
+            return null;
+        }
+
+        private static string GetDisplayNameForProperty(Type containerType, string propertyName) {
+            ICustomTypeDescriptor typeDescriptor = GetTypeDescriptor(containerType);
+            PropertyDescriptor property = typeDescriptor.GetProperties().Find(propertyName, true);
+            if (property == null) {
+                throw new ArgumentException(String.Format(CultureInfo.CurrentCulture,
+                    DataAnnotationsResources.Common_PropertyNotFound, containerType.FullName, propertyName));
+            }
+            IEnumerable<Attribute> attributes = property.Attributes.Cast<Attribute>();
+            DisplayAttribute display = attributes.OfType<DisplayAttribute>().FirstOrDefault();
+            if (display != null) {
+                return display.GetName();
+            }
+            DisplayNameAttribute displayName = attributes.OfType<DisplayNameAttribute>().FirstOrDefault();
+            if (displayName != null) {
+                return displayName.DisplayName;
+            }
+            return propertyName;
+        }
+
+        private static ICustomTypeDescriptor GetTypeDescriptor(Type type) {
+            return new AssociatedMetadataTypeTypeDescriptionProvider(type).GetTypeDescriptor(type);
+        }
+
+    }
+}