Imported Upstream version 4.0.0~alpha1

Former-commit-id: 806294f5ded97629b74c85c09952f2a74fe182d9

external/referencesource/System.Web/ModelBinding/CollectionModelBinder`1.cs

@@ -0,0 +1,111 @@
+namespace System.Web.ModelBinding {
+    using System.Collections;
+    using System.Collections.Generic;
+    using System.Globalization;
+
+    public class CollectionModelBinder<TElement> : IModelBinder {
+
+        // Used when the ValueProvider contains the collection to be bound as multiple elements, e.g. foo[0], foo[1].
+        private static List<TElement> BindComplexCollection(ModelBindingExecutionContext modelBindingExecutionContext, ModelBindingContext bindingContext) {
+            string indexPropertyName = ModelBinderUtil.CreatePropertyModelName(bindingContext.ModelName, "index");
+            ValueProviderResult vpResultIndex = bindingContext.UnvalidatedValueProvider.GetValue(indexPropertyName);
+            IEnumerable<string> indexNames = CollectionModelBinderUtil.GetIndexNamesFromValueProviderResult(vpResultIndex);
+            return BindComplexCollectionFromIndexes(modelBindingExecutionContext, bindingContext, indexNames);
+        }
+
+        internal static List<TElement> BindComplexCollectionFromIndexes(ModelBindingExecutionContext modelBindingExecutionContext, ModelBindingContext bindingContext, IEnumerable<string> indexNames) {
+            bool indexNamesIsFinite;
+            if (indexNames != null) {
+                indexNamesIsFinite = true;
+            }
+            else {
+                indexNamesIsFinite = false;
+                indexNames = CollectionModelBinderUtil.GetZeroBasedIndexes();
+            }
+
+            List<TElement> boundCollection = new List<TElement>();
+            foreach (string indexName in indexNames) {
+                string fullChildName = ModelBinderUtil.CreateIndexModelName(bindingContext.ModelName, indexName);
+                ModelBindingContext childBindingContext = new ModelBindingContext(bindingContext) {
+                    ModelMetadata = ModelMetadataProviders.Current.GetMetadataForType(null, typeof(TElement)),
+                    ModelName = fullChildName
+                };
+
+                object boundValue = null;
+                IModelBinder childBinder = bindingContext.ModelBinderProviders.GetBinder(modelBindingExecutionContext, childBindingContext);
+                if (childBinder != null) {
+                    if (childBinder.BindModel(modelBindingExecutionContext, childBindingContext)) {
+                        boundValue = childBindingContext.Model;
+
+                        // merge validation up
+                        bindingContext.ValidationNode.ChildNodes.Add(childBindingContext.ValidationNode);
+                    }
+                }
+                else {
+                    // should we even bother continuing?
+                    if (!indexNamesIsFinite) {
+                        break;
+                    }
+                }
+
+                boundCollection.Add(ModelBinderUtil.CastOrDefault<TElement>(boundValue));
+            }
+
+            return boundCollection;
+        }
+
+        public virtual bool BindModel(ModelBindingExecutionContext modelBindingExecutionContext, ModelBindingContext bindingContext) {
+            ModelBinderUtil.ValidateBindingContext(bindingContext);
+
+            ValueProviderResult vpResult = bindingContext.UnvalidatedValueProvider.GetValue(bindingContext.ModelName, skipValidation: !bindingContext.ValidateRequest);
+            List<TElement> boundCollection = (vpResult != null)
+                ? BindSimpleCollection(modelBindingExecutionContext, bindingContext, vpResult.RawValue, vpResult.Culture)
+                : BindComplexCollection(modelBindingExecutionContext, bindingContext);
+
+            bool retVal = CreateOrReplaceCollection(modelBindingExecutionContext, bindingContext, boundCollection);
+            return retVal;
+        }
+
+        // Used when the ValueProvider contains the collection to be bound as a single element, e.g. the raw value
+        // is [ "1", "2" ] and needs to be converted to an int[].
+        internal static List<TElement> BindSimpleCollection(ModelBindingExecutionContext modelBindingExecutionContext, ModelBindingContext bindingContext, object rawValue, CultureInfo culture) {
+            if (rawValue == null) {
+                return null; // nothing to do
+            }
+
+            List<TElement> boundCollection = new List<TElement>();
+
+            object[] rawValueArray = ModelBinderUtil.RawValueToObjectArray(rawValue);
+            foreach (object rawValueElement in rawValueArray) {
+                ModelBindingContext innerBindingContext = new ModelBindingContext(bindingContext) {
+                    ModelMetadata = ModelMetadataProviders.Current.GetMetadataForType(null, typeof(TElement)),
+                    ModelName = bindingContext.ModelName,
+                    ValueProvider = new ValueProviderCollection() { // aggregate value provider
+                        new ElementalValueProvider(bindingContext.ModelName, rawValueElement, culture), // our temporary provider goes at the front of the list
+                        bindingContext.ValueProvider
+                    }
+                };
+
+                object boundValue = null;
+                IModelBinder childBinder = bindingContext.ModelBinderProviders.GetBinder(modelBindingExecutionContext, innerBindingContext);
+                if (childBinder != null) {
+                    if (childBinder.BindModel(modelBindingExecutionContext, innerBindingContext)) {
+                        boundValue = innerBindingContext.Model;
+                        bindingContext.ValidationNode.ChildNodes.Add(innerBindingContext.ValidationNode);
+                    }
+                }
+                boundCollection.Add(ModelBinderUtil.CastOrDefault<TElement>(boundValue));
+            }
+
+            return boundCollection;
+        }
+
+        // Extensibility point that allows the bound collection to be manipulated or transformed before
+        // being returned from the binder.
+        protected virtual bool CreateOrReplaceCollection(ModelBindingExecutionContext modelBindingExecutionContext, ModelBindingContext bindingContext, IList<TElement> newCollection) {
+            CollectionModelBinderUtil.CreateOrReplaceCollection(bindingContext, newCollection, () => new List<TElement>());
+            return true;
+        }
+
+    }
+}