/* ****************************************************************************
*
* Copyright (c) Microsoft Corporation. All rights reserved.
*
* This software is subject to the Microsoft Public License (Ms-PL).
* A copy of the license can be found in the license.htm file included
* in this distribution.
*
* You must not remove this notice, or any other, from this software.
*
* ***************************************************************************/
namespace System.Web.Mvc{
using System;
using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.Linq;
using System.Reflection;
using System.Runtime.CompilerServices;
using System.Web.Mvc.Resources;
public class DefaultModelBinder : IModelBinder {
private ModelBinderDictionary _binders;
private static string _resourceClassKey;
[SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly",
Justification = "Property is settable so that the dictionary can be provided for unit testing purposes.")]
protected internal ModelBinderDictionary Binders {
get {
if (_binders == null) {
_binders = ModelBinders.Binders;
}
return _binders;
}
set {
_binders = value;
}
}
public static string ResourceClassKey {
get {
return _resourceClassKey ?? String.Empty;
}
set {
_resourceClassKey = value;
}
}
private static void AddValueRequiredMessageToModelState(ControllerContext controllerContext, ModelStateDictionary modelState, string modelStateKey, Type elementType, object value) {
if (value == null && !TypeHelpers.TypeAllowsNullValue(elementType) && modelState.IsValidField(modelStateKey)) {
modelState.AddModelError(modelStateKey, GetValueRequiredResource(controllerContext));
}
}
internal void BindComplexElementalModel(ControllerContext controllerContext, ModelBindingContext bindingContext, object model) {
// need to replace the property filter + model object and create an inner binding context
ModelBindingContext newBindingContext = CreateComplexElementalModelBindingContext(controllerContext, bindingContext, model);
// validation
if (OnModelUpdating(controllerContext, newBindingContext)) {
BindProperties(controllerContext, newBindingContext);
OnModelUpdated(controllerContext, newBindingContext);
}
}
internal object BindComplexModel(ControllerContext controllerContext, ModelBindingContext bindingContext) {
object model = bindingContext.Model;
Type modelType = bindingContext.ModelType;
// if we're being asked to create an array, create a list instead, then coerce to an array after the list is created
if (model == null && modelType.IsArray) {
Type elementType = modelType.GetElementType();
Type listType = typeof(List<>).MakeGenericType(elementType);
object collection = CreateModel(controllerContext, bindingContext, listType);
ModelBindingContext arrayBindingContext = new ModelBindingContext() {
ModelMetadata = ModelMetadataProviders.Current.GetMetadataForType(() => collection, listType),
ModelName = bindingContext.ModelName,
ModelState = bindingContext.ModelState,
PropertyFilter = bindingContext.PropertyFilter,
ValueProvider = bindingContext.ValueProvider
};
IList list = (IList)UpdateCollection(controllerContext, arrayBindingContext, elementType);
if (list == null) {
return null;
}
Array array = Array.CreateInstance(elementType, list.Count);
list.CopyTo(array, 0);
return array;
}
if (model == null) {
model = CreateModel(controllerContext, bindingContext, modelType);
}
// special-case IDictionary<,> and ICollection<>
Type dictionaryType = TypeHelpers.ExtractGenericInterface(modelType, typeof(IDictionary<,>));
if (dictionaryType != null) {
Type[] genericArguments = dictionaryType.GetGenericArguments();
Type keyType = genericArguments[0];
Type valueType = genericArguments[1];
ModelBindingContext dictionaryBindingContext = new ModelBindingContext() {
ModelMetadata = ModelMetadataProviders.Current.GetMetadataForType(() => model, modelType),
ModelName = bindingContext.ModelName,
ModelState = bindingContext.ModelState,
PropertyFilter = bindingContext.PropertyFilter,
ValueProvider = bindingContext.ValueProvider
};
object dictionary = UpdateDictionary(controllerContext, dictionaryBindingContext, keyType, valueType);
return dictionary;
}
Type enumerableType = TypeHelpers.ExtractGenericInterface(modelType, typeof(IEnumerable<>));
if (enumerableType != null) {
Type elementType = enumerableType.GetGenericArguments()[0];
Type collectionType = typeof(ICollection<>).MakeGenericType(elementType);
if (collectionType.IsInstanceOfType(model)) {
ModelBindingContext collectionBindingContext = new ModelBindingContext() {
ModelMetadata = ModelMetadataProviders.Current.GetMetadataForType(() => model, modelType),
ModelName = bindingContext.ModelName,
ModelState = bindingContext.ModelState,
PropertyFilter = bindingContext.PropertyFilter,
ValueProvider = bindingContext.ValueProvider
};
object collection = UpdateCollection(controllerContext, collectionBindingContext, elementType);
return collection;
}
}
// otherwise, just update the properties on the complex type
BindComplexElementalModel(controllerContext, bindingContext, model);
return model;
}
public virtual object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext) {
if (bindingContext == null) {
throw new ArgumentNullException("bindingContext");
}
bool performedFallback = false;
if (!String.IsNullOrEmpty(bindingContext.ModelName) && !bindingContext.ValueProvider.ContainsPrefix(bindingContext.ModelName)) {
// We couldn't find any entry that began with the prefix. If this is the top-level element, fall back
// to the empty prefix.
if (bindingContext.FallbackToEmptyPrefix) {
bindingContext = new ModelBindingContext() {
ModelMetadata = bindingContext.ModelMetadata,
ModelState = bindingContext.ModelState,
PropertyFilter = bindingContext.PropertyFilter,
ValueProvider = bindingContext.ValueProvider
};
performedFallback = true;
}
else {
return null;
}
}
// Simple model = int, string, etc.; determined by calling TypeConverter.CanConvertFrom(typeof(string))
// or by seeing if a value in the request exactly matches the name of the model we're binding.
// Complex type = everything else.
if (!performedFallback) {
ValueProviderResult vpResult = bindingContext.ValueProvider.GetValue(bindingContext.ModelName);
if (vpResult != null) {
return BindSimpleModel(controllerContext, bindingContext, vpResult);
}
}
if (!bindingContext.ModelMetadata.IsComplexType) {
return null;
}
return BindComplexModel(controllerContext, bindingContext);
}
private void BindProperties(ControllerContext controllerContext, ModelBindingContext bindingContext) {
IEnumerable<PropertyDescriptor> properties = GetFilteredModelProperties(controllerContext, bindingContext);
foreach (PropertyDescriptor property in properties) {
BindProperty(controllerContext, bindingContext, property);
}
}
protected virtual void BindProperty(ControllerContext controllerContext, ModelBindingContext bindingContext, PropertyDescriptor propertyDescriptor) {
// need to skip properties that aren't part of the request, else we might hit a StackOverflowException
string fullPropertyKey = CreateSubPropertyName(bindingContext.ModelName, propertyDescriptor.Name);
if (!bindingContext.ValueProvider.ContainsPrefix(fullPropertyKey)) {
return;
}
// call into the property's model binder
IModelBinder propertyBinder = Binders.GetBinder(propertyDescriptor.PropertyType);
object originalPropertyValue = propertyDescriptor.GetValue(bindingContext.Model);
ModelMetadata propertyMetadata = bindingContext.PropertyMetadata[propertyDescriptor.Name];
propertyMetadata.Model = originalPropertyValue;
ModelBindingContext innerBindingContext = new ModelBindingContext() {
ModelMetadata = propertyMetadata,
ModelName = fullPropertyKey,
ModelState = bindingContext.ModelState,
ValueProvider = bindingContext.ValueProvider
};
object newPropertyValue = GetPropertyValue(controllerContext, innerBindingContext, propertyDescriptor, propertyBinder);
propertyMetadata.Model = newPropertyValue;
// validation
ModelState modelState = bindingContext.ModelState[fullPropertyKey];
if (modelState == null || modelState.Errors.Count == 0) {
if (OnPropertyValidating(controllerContext, bindingContext, propertyDescriptor, newPropertyValue)) {
SetProperty(controllerContext, bindingContext, propertyDescriptor, newPropertyValue);
OnPropertyValidated(controllerContext, bindingContext, propertyDescriptor, newPropertyValue);
}
}
else {
SetProperty(controllerContext, bindingContext, propertyDescriptor, newPropertyValue);
// Convert FormatExceptions (type conversion failures) into InvalidValue messages
foreach (ModelError error in modelState.Errors.Where(err => String.IsNullOrEmpty(err.ErrorMessage) && err.Exception != null).ToList()) {
for (Exception exception = error.Exception; exception != null; exception = exception.InnerException) {
if (exception is FormatException) {
string displayName = propertyMetadata.GetDisplayName();
string errorMessageTemplate = GetValueInvalidResource(controllerContext);
string errorMessage = String.Format(CultureInfo.CurrentUICulture, errorMessageTemplate, modelState.Value.AttemptedValue, displayName);
modelState.Errors.Remove(error);
modelState.Errors.Add(errorMessage);
break;
}
}
}
}
}
internal object BindSimpleModel(ControllerContext controllerContext, ModelBindingContext bindingContext, ValueProviderResult valueProviderResult) {
bindingContext.ModelState.SetModelValue(bindingContext.ModelName, valueProviderResult);
// if the value provider returns an instance of the requested data type, we can just short-circuit
// the evaluation and return that instance
if (bindingContext.ModelType.IsInstanceOfType(valueProviderResult.RawValue)) {
return valueProviderResult.RawValue;
}
// since a string is an IEnumerable<char>, we want it to skip the two checks immediately following
if (bindingContext.ModelType != typeof(string)) {
// conversion results in 3 cases, as below
if (bindingContext.ModelType.IsArray) {
// case 1: user asked for an array
// ValueProviderResult.ConvertTo() understands array types, so pass in the array type directly
object modelArray = ConvertProviderResult(bindingContext.ModelState, bindingContext.ModelName, valueProviderResult, bindingContext.ModelType);
return modelArray;
}
Type enumerableType = TypeHelpers.ExtractGenericInterface(bindingContext.ModelType, typeof(IEnumerable<>));
if (enumerableType != null) {
// case 2: user asked for a collection rather than an array
// need to call ConvertTo() on the array type, then copy the array to the collection
object modelCollection = CreateModel(controllerContext, bindingContext, bindingContext.ModelType);
Type elementType = enumerableType.GetGenericArguments()[0];
Type arrayType = elementType.MakeArrayType();
object modelArray = ConvertProviderResult(bindingContext.ModelState, bindingContext.ModelName, valueProviderResult, arrayType);
Type collectionType = typeof(ICollection<>).MakeGenericType(elementType);
if (collectionType.IsInstanceOfType(modelCollection)) {
CollectionHelpers.ReplaceCollection(elementType, modelCollection, modelArray);
}
return modelCollection;
}
}
// case 3: user asked for an individual element
object model = ConvertProviderResult(bindingContext.ModelState, bindingContext.ModelName, valueProviderResult, bindingContext.ModelType);
return model;
}
private static bool CanUpdateReadonlyTypedReference(Type type) {
// value types aren't strictly immutable, but because they have copy-by-value semantics
// we can't update a value type that is marked readonly
if (type.IsValueType) {
return false;
}
// arrays are mutable, but because we can't change their length we shouldn't try
// to update an array that is referenced readonly
if (type.IsArray) {
return false;
}
// special-case known common immutable types
if (type == typeof(string)) {
return false;
}
return true;
}
[SuppressMessage("Microsoft.Globalization", "CA1304:SpecifyCultureInfo", MessageId = "System.Web.Mvc.ValueProviderResult.ConvertTo(System.Type)",
Justification = "The target object should make the correct culture determination, not this method.")]
[SuppressMessage("Microsoft.Design", "CA1031:DoNotCatchGeneralExceptionTypes",
Justification = "We're recording this exception so that we can act on it later.")]
private static object ConvertProviderResult(ModelStateDictionary modelState, string modelStateKey, ValueProviderResult valueProviderResult, Type destinationType) {
try {
object convertedValue = valueProviderResult.ConvertTo(destinationType);
return convertedValue;
}
catch (Exception ex) {
modelState.AddModelError(modelStateKey, ex);
return null;
}
}
internal ModelBindingContext CreateComplexElementalModelBindingContext(ControllerContext controllerContext, ModelBindingContext bindingContext, object model) {
BindAttribute bindAttr = (BindAttribute)GetTypeDescriptor(controllerContext, bindingContext).GetAttributes()[typeof(BindAttribute)];
Predicate<string> newPropertyFilter = (bindAttr != null)
? propertyName => bindAttr.IsPropertyAllowed(propertyName) && bindingContext.PropertyFilter(propertyName)
: bindingContext.PropertyFilter;
ModelBindingContext newBindingContext = new ModelBindingContext() {
ModelMetadata = ModelMetadataProviders.Current.GetMetadataForType(() => model, bindingContext.ModelType),
ModelName = bindingContext.ModelName,
ModelState = bindingContext.ModelState,
PropertyFilter = newPropertyFilter,
ValueProvider = bindingContext.ValueProvider
};
return newBindingContext;
}
protected virtual object CreateModel(ControllerContext controllerContext, ModelBindingContext bindingContext, Type modelType) {
Type typeToCreate = modelType;
// we can understand some collection interfaces, e.g. IList<>, IDictionary<,>
if (modelType.IsGenericType) {
Type genericTypeDefinition = modelType.GetGenericTypeDefinition();
if (genericTypeDefinition == typeof(IDictionary<,>)) {
typeToCreate = typeof(Dictionary<,>).MakeGenericType(modelType.GetGenericArguments());
}
else if (genericTypeDefinition == typeof(IEnumerable<>) || genericTypeDefinition == typeof(ICollection<>) || genericTypeDefinition == typeof(IList<>)) {
typeToCreate = typeof(List<>).MakeGenericType(modelType.GetGenericArguments());
}
}
// fallback to the type's default constructor
return Activator.CreateInstance(typeToCreate);
}
protected static string CreateSubIndexName(string prefix, int index) {
return String.Format(CultureInfo.InvariantCulture, "{0}[{1}]", prefix, index);
}
protected static string CreateSubIndexName(string prefix, string index) {
return String.Format(CultureInfo.InvariantCulture, "{0}[{1}]", prefix, index);
}
protected internal static string CreateSubPropertyName(string prefix, string propertyName) {
if (String.IsNullOrEmpty(prefix)) {
return propertyName;
}
else if (String.IsNullOrEmpty(propertyName)) {
return prefix;
}
else {
return prefix + "." + propertyName;
}
}
protected IEnumerable<PropertyDescriptor> GetFilteredModelProperties(ControllerContext controllerContext, ModelBindingContext bindingContext) {
PropertyDescriptorCollection properties = GetModelProperties(controllerContext, bindingContext);
Predicate<string> propertyFilter = bindingContext.PropertyFilter;
return from PropertyDescriptor property in properties
where ShouldUpdateProperty(property, propertyFilter)
select property;
}
[SuppressMessage("Microsoft.Globalization", "CA1304:SpecifyCultureInfo", MessageId = "System.Web.Mvc.ValueProviderResult.ConvertTo(System.Type)",
Justification = "ValueProviderResult already handles culture conversion appropriately.")]
private static void GetIndexes(ModelBindingContext bindingContext, out bool stopOnIndexNotFound, out IEnumerable<string> indexes) {
string indexKey = CreateSubPropertyName(bindingContext.ModelName, "index");
ValueProviderResult vpResult = bindingContext.ValueProvider.GetValue(indexKey);
if (vpResult != null) {
string[] indexesArray = vpResult.ConvertTo(typeof(string[])) as string[];
if (indexesArray != null) {
stopOnIndexNotFound = false;
indexes = indexesArray;
return;
}
}
// just use a simple zero-based system
stopOnIndexNotFound = true;
indexes = GetZeroBasedIndexes();
}
protected virtual PropertyDescriptorCollection GetModelProperties(ControllerContext controllerContext, ModelBindingContext bindingContext) {
return GetTypeDescriptor(controllerContext, bindingContext).GetProperties();
}
protected virtual object GetPropertyValue(ControllerContext controllerContext, ModelBindingContext bindingContext, PropertyDescriptor propertyDescriptor, IModelBinder propertyBinder) {
object value = propertyBinder.BindModel(controllerContext, bindingContext);
if (bindingContext.ModelMetadata.ConvertEmptyStringToNull && Object.Equals(value, String.Empty)) {
return null;
}
return value;
}
protected virtual ICustomTypeDescriptor GetTypeDescriptor(ControllerContext controllerContext, ModelBindingContext bindingContext) {
return TypeDescriptorHelper.Get(bindingContext.ModelType);
}
// If the user specified a ResourceClassKey try to load the resource they specified.
// If the class key is invalid, an exception will be thrown.
// If the class key is valid but the resource is not found, it returns null, in which
// case it will fall back to the MVC default error message.
private static string GetUserResourceString(ControllerContext controllerContext, string resourceName) {
string result = null;
if (!String.IsNullOrEmpty(ResourceClassKey) && (controllerContext != null) && (controllerContext.HttpContext != null)) {
result = controllerContext.HttpContext.GetGlobalResourceObject(ResourceClassKey, resourceName, CultureInfo.CurrentUICulture) as string;
}
return result;
}
private static string GetValueInvalidResource(ControllerContext controllerContext) {
return GetUserResourceString(controllerContext, "PropertyValueInvalid") ?? MvcResources.DefaultModelBinder_ValueInvalid;
}
private static string GetValueRequiredResource(ControllerContext controllerContext) {
return GetUserResourceString(controllerContext, "PropertyValueRequired") ?? MvcResources.DefaultModelBinder_ValueRequired;
}
private static IEnumerable<string> GetZeroBasedIndexes() {
for (int i = 0; ; i++) {
yield return i.ToString(CultureInfo.InvariantCulture);
}
}
protected static bool IsModelValid(ModelBindingContext bindingContext) {
if (bindingContext == null) {
throw new ArgumentNullException("bindingContext");
}
if (String.IsNullOrEmpty(bindingContext.ModelName)) {
return bindingContext.ModelState.IsValid;
}
return bindingContext.ModelState.IsValidField(bindingContext.ModelName);
}
protected virtual void OnModelUpdated(ControllerContext controllerContext, ModelBindingContext bindingContext) {
Dictionary<string, bool> startedValid = new Dictionary<string, bool>(StringComparer.OrdinalIgnoreCase);
foreach (ModelValidationResult validationResult in ModelValidator.GetModelValidator(bindingContext.ModelMetadata, controllerContext).Validate(null)) {
string subPropertyName = CreateSubPropertyName(bindingContext.ModelName, validationResult.MemberName);
if (!startedValid.ContainsKey(subPropertyName)) {
startedValid[subPropertyName] = bindingContext.ModelState.IsValidField(subPropertyName);
}
if (startedValid[subPropertyName]) {
bindingContext.ModelState.AddModelError(subPropertyName, validationResult.Message);
}
}
}
protected virtual bool OnModelUpdating(ControllerContext controllerContext, ModelBindingContext bindingContext) {
// default implementation does nothing
return true;
}
protected virtual void OnPropertyValidated(ControllerContext controllerContext, ModelBindingContext bindingContext, PropertyDescriptor propertyDescriptor, object value) {
// default implementation does nothing
}
protected virtual bool OnPropertyValidating(ControllerContext controllerContext, ModelBindingContext bindingContext, PropertyDescriptor propertyDescriptor, object value) {
// default implementation does nothing
return true;
}
[SuppressMessage("Microsoft.Design", "CA1031:DoNotCatchGeneralExceptionTypes",
Justification = "We're recording this exception so that we can act on it later.")]
protected virtual void SetProperty(ControllerContext controllerContext, ModelBindingContext bindingContext, PropertyDescriptor propertyDescriptor, object value) {
ModelMetadata propertyMetadata = bindingContext.PropertyMetadata[propertyDescriptor.Name];
propertyMetadata.Model = value;
string modelStateKey = CreateSubPropertyName(bindingContext.ModelName, propertyMetadata.PropertyName);
// If the value is null, and the validation system can find a Required validator for
// us, we'd prefer to run it before we attempt to set the value; otherwise, property
// setters which throw on null (f.e., Entity Framework properties which are backed by
// non-nullable strings in the DB) will get their error message in ahead of us.
//
// We are effectively using the special validator -- Required -- as a helper to the
// binding system, which is why this code is here instead of in the Validating/Validated
// methods, which are really the old-school validation hooks.
if (value == null && bindingContext.ModelState.IsValidField(modelStateKey)) {
ModelValidator requiredValidator = ModelValidatorProviders.Providers.GetValidators(propertyMetadata, controllerContext).Where(v => v.IsRequired).FirstOrDefault();
if (requiredValidator != null) {
foreach (ModelValidationResult validationResult in requiredValidator.Validate(bindingContext.Model)) {
bindingContext.ModelState.AddModelError(modelStateKey, validationResult.Message);
}
}
}
bool isNullValueOnNonNullableType =
value == null &&
!TypeHelpers.TypeAllowsNullValue(propertyDescriptor.PropertyType);
// Try to set a value into the property unless we know it will fail (read-only
// properties and null values with non-nullable types)
if (!propertyDescriptor.IsReadOnly && !isNullValueOnNonNullableType) {
try {
propertyDescriptor.SetValue(bindingContext.Model, value);
}
catch (Exception ex) {
// Only add if we're not already invalid
if (bindingContext.ModelState.IsValidField(modelStateKey)) {
bindingContext.ModelState.AddModelError(modelStateKey, ex);
}
}
}
// Last chance for an error on null values with non-nullable types, we'll use
// the default "A value is required." message.
if (isNullValueOnNonNullableType && bindingContext.ModelState.IsValidField(modelStateKey)) {
bindingContext.ModelState.AddModelError(modelStateKey, GetValueRequiredResource(controllerContext));
}
}
private static bool ShouldUpdateProperty(PropertyDescriptor property, Predicate<string> propertyFilter) {
if (property.IsReadOnly && !CanUpdateReadonlyTypedReference(property.PropertyType)) {
return false;
}
// if this property is rejected by the filter, move on
if (!propertyFilter(property.Name)) {
return false;
}
// otherwise, allow
return true;
}
internal object UpdateCollection(ControllerContext controllerContext, ModelBindingContext bindingContext, Type elementType) {
bool stopOnIndexNotFound;
IEnumerable<string> indexes;
GetIndexes(bindingContext, out stopOnIndexNotFound, out indexes);
IModelBinder elementBinder = Binders.GetBinder(elementType);
// build up a list of items from the request
List<object> modelList = new List<object>();
foreach (string currentIndex in indexes) {
string subIndexKey = CreateSubIndexName(bindingContext.ModelName, currentIndex);
if (!bindingContext.ValueProvider.ContainsPrefix(subIndexKey)) {
if (stopOnIndexNotFound) {
// we ran out of elements to pull
break;
}
else {
continue;
}
}
ModelBindingContext innerContext = new ModelBindingContext() {
ModelMetadata = ModelMetadataProviders.Current.GetMetadataForType(null, elementType),
ModelName = subIndexKey,
ModelState = bindingContext.ModelState,
PropertyFilter = bindingContext.PropertyFilter,
ValueProvider = bindingContext.ValueProvider
};
object thisElement = elementBinder.BindModel(controllerContext, innerContext);
// we need to merge model errors up
AddValueRequiredMessageToModelState(controllerContext, bindingContext.ModelState, subIndexKey, elementType, thisElement);
modelList.Add(thisElement);
}
// if there weren't any elements at all in the request, just return
if (modelList.Count == 0) {
return null;
}
// replace the original collection
object collection = bindingContext.Model;
CollectionHelpers.ReplaceCollection(elementType, collection, modelList);
return collection;
}
internal object UpdateDictionary(ControllerContext controllerContext, ModelBindingContext bindingContext, Type keyType, Type valueType) {
bool stopOnIndexNotFound;
IEnumerable<string> indexes;
GetIndexes(bindingContext, out stopOnIndexNotFound, out indexes);
IModelBinder keyBinder = Binders.GetBinder(keyType);
IModelBinder valueBinder = Binders.GetBinder(valueType);
// build up a list of items from the request
List<KeyValuePair<object, object>> modelList = new List<KeyValuePair<object, object>>();
foreach (string currentIndex in indexes) {
string subIndexKey = CreateSubIndexName(bindingContext.ModelName, currentIndex);
string keyFieldKey = CreateSubPropertyName(subIndexKey, "key");
string valueFieldKey = CreateSubPropertyName(subIndexKey, "value");
if (!(bindingContext.ValueProvider.ContainsPrefix(keyFieldKey) && bindingContext.ValueProvider.ContainsPrefix(valueFieldKey))) {
if (stopOnIndexNotFound) {
// we ran out of elements to pull
break;
}
else {
continue;
}
}
// bind the key
ModelBindingContext keyBindingContext = new ModelBindingContext() {
ModelMetadata = ModelMetadataProviders.Current.GetMetadataForType(null, keyType),
ModelName = keyFieldKey,
ModelState = bindingContext.ModelState,
ValueProvider = bindingContext.ValueProvider
};
object thisKey = keyBinder.BindModel(controllerContext, keyBindingContext);
// we need to merge model errors up
AddValueRequiredMessageToModelState(controllerContext, bindingContext.ModelState, keyFieldKey, keyType, thisKey);
if (!keyType.IsInstanceOfType(thisKey)) {
// we can't add an invalid key, so just move on
continue;
}
// bind the value
ModelBindingContext valueBindingContext = new ModelBindingContext() {
ModelMetadata = ModelMetadataProviders.Current.GetMetadataForType(null, valueType),
ModelName = valueFieldKey,
ModelState = bindingContext.ModelState,
PropertyFilter = bindingContext.PropertyFilter,
ValueProvider = bindingContext.ValueProvider
};
object thisValue = valueBinder.BindModel(controllerContext, valueBindingContext);
// we need to merge model errors up
AddValueRequiredMessageToModelState(controllerContext, bindingContext.ModelState, valueFieldKey, valueType, thisValue);
KeyValuePair<object, object> kvp = new KeyValuePair<object, object>(thisKey, thisValue);
modelList.Add(kvp);
}
// if there weren't any elements at all in the request, just return
if (modelList.Count == 0) {
return null;
}
// replace the original collection
object dictionary = bindingContext.Model;
CollectionHelpers.ReplaceDictionary(keyType, valueType, dictionary, modelList);
return dictionary;
}
// This helper type is used because we're working with strongly-typed collections, but we don't know the Ts
// ahead of time. By using the generic methods below, we can consolidate the collection-specific code in a
// single helper type rather than having reflection-based calls spread throughout the DefaultModelBinder type.
// There is a single point of entry to each of the methods below, so they're fairly simple to maintain.
private static class CollectionHelpers {
private static readonly MethodInfo _replaceCollectionMethod = typeof(CollectionHelpers).GetMethod("ReplaceCollectionImpl", BindingFlags.Static | BindingFlags.NonPublic);
private static readonly MethodInfo _replaceDictionaryMethod = typeof(CollectionHelpers).GetMethod("ReplaceDictionaryImpl", BindingFlags.Static | BindingFlags.NonPublic);
[MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.NoOptimization)]
public static void ReplaceCollection(Type collectionType, object collection, object newContents) {
MethodInfo targetMethod = _replaceCollectionMethod.MakeGenericMethod(collectionType);
targetMethod.Invoke(null, new object[] { collection, newContents });
}
private static void ReplaceCollectionImpl<T>(ICollection<T> collection, IEnumerable newContents) {
collection.Clear();
if (newContents != null) {
foreach (object item in newContents) {
// if the item was not a T, some conversion failed. the error message will be propagated,
// but in the meanwhile we need to make a placeholder element in the array.
T castItem = (item is T) ? (T)item : default(T);
collection.Add(castItem);
}
}
}
[MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.NoOptimization)]
public static void ReplaceDictionary(Type keyType, Type valueType, object dictionary, object newContents) {
MethodInfo targetMethod = _replaceDictionaryMethod.MakeGenericMethod(keyType, valueType);
targetMethod.Invoke(null, new object[] { dictionary, newContents });
}
private static void ReplaceDictionaryImpl<TKey, TValue>(IDictionary<TKey, TValue> dictionary, IEnumerable<KeyValuePair<object, object>> newContents) {
dictionary.Clear();
foreach (KeyValuePair<object, object> item in newContents) {
// if the item was not a T, some conversion failed. the error message will be propagated,
// but in the meanwhile we need to make a placeholder element in the dictionary.
TKey castKey = (TKey)item.Key; // this cast shouldn't fail
TValue castValue = (item.Value is TValue) ? (TValue)item.Value : default(TValue);
dictionary[castKey] = castValue;
}
}
}
}
}
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