Imported Upstream version 4.0.0~alpha1

Former-commit-id: 806294f5ded97629b74c85c09952f2a74fe182d9

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

@@ -0,0 +1,61 @@
+namespace System.Web.ModelBinding {
+
+    public static class ModelBinders {
+
+        private static readonly ModelBinderDictionary _binders = CreateDefaultBinderDictionary();
+
+        public static ModelBinderDictionary Binders {
+            get {
+                return _binders;
+            }
+        }
+#if UNDEF
+        internal static IModelBinder GetBinderFromAttributes(Type type, Func<string> errorMessageAccessor) {
+            AttributeCollection allAttrs = TypeDescriptorHelper.Get(type).GetAttributes();
+            CustomModelBinderAttribute[] filteredAttrs = allAttrs.OfType<CustomModelBinderAttribute>().ToArray();
+            return GetBinderFromAttributesImpl(filteredAttrs, errorMessageAccessor);
+        }
+
+        internal static IModelBinder GetBinderFromAttributes(ICustomAttributeProvider element, Func<string> errorMessageAccessor) {
+            CustomModelBinderAttribute[] attrs = (CustomModelBinderAttribute[])element.GetCustomAttributes(typeof(CustomModelBinderAttribute), true /* inherit */);
+            return GetBinderFromAttributesImpl(attrs, errorMessageAccessor);
+        }
+
+        private static IModelBinder GetBinderFromAttributesImpl(CustomModelBinderAttribute[] attrs, Func<string> errorMessageAccessor) {
+            // this method is used to get a custom binder based on the attributes of the element passed to it.
+            // it will return null if a binder cannot be detected based on the attributes alone.
+
+            if (attrs == null) {
+                return null;
+            }
+
+            switch (attrs.Length) {
+                case 0:
+                    return null;
+
+                case 1:
+                    IModelBinder binder = attrs[0].GetBinder();
+                    return binder;
+
+                default:
+                    string errorMessage = errorMessageAccessor();
+                    throw new InvalidOperationException(errorMessage);
+            }
+        }
+#endif
+        private static ModelBinderDictionary CreateDefaultBinderDictionary() {
+            // We can't add a binder to the HttpPostedFileBase type as an attribute, so we'll just
+            // prepopulate the dictionary as a convenience to users.
+
+            ModelBinderDictionary binders = new ModelBinderDictionary() {
+#if UNDEF
+                { typeof(HttpPostedFileBase), new HttpPostedFileBaseModelBinder() },
+                { typeof(byte[]), new ByteArrayModelBinder() },
+                { typeof(Binary), new LinqBinaryModelBinder() }
+#endif
+            };
+            return binders;
+        }
+
+    }
+}