internal async Task <ModelBindingResult> TryBindStrongModel <TModel>(ModelBindingContext parentBindingContext,
string propertyName)
{
var propertyModelMetadata =
parentBindingContext.OperationBindingContext.MetadataProvider.GetMetadataForType(typeof(TModel));
var propertyModelName =
ModelBindingHelper.CreatePropertyModelName(parentBindingContext.ModelName, propertyName);
var propertyBindingContext = ModelBindingContext.GetChildModelBindingContext(
parentBindingContext,
propertyModelName,
propertyModelMetadata);
propertyBindingContext.BinderModelName = propertyModelMetadata.BinderModelName;
var modelBindingResult = await propertyBindingContext.OperationBindingContext.ModelBinder.BindModelAsync(
propertyBindingContext);
if (modelBindingResult != null)
{
return(modelBindingResult);
}
// Always return a ModelBindingResult to avoid an NRE in BindModelAsync.
return(new ModelBindingResult(model: default(TModel), key: propertyModelName, isModelSet: false));
}
// 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 async Task <CollectionResult> BindSimpleCollection(
ModelBindingContext bindingContext,
object rawValue,
CultureInfo culture)
{
if (rawValue == null)
{
return(null); // nothing to do
}
var boundCollection = new List <TElement>();
var metadataProvider = bindingContext.OperationBindingContext.MetadataProvider;
var elementMetadata = metadataProvider.GetMetadataForType(typeof(TElement));
var validationNode = new ModelValidationNode(
bindingContext.ModelName,
bindingContext.ModelMetadata,
boundCollection);
var rawValueArray = RawValueToObjectArray(rawValue);
foreach (var rawValueElement in rawValueArray)
{
var innerBindingContext = ModelBindingContext.GetChildModelBindingContext(
bindingContext,
bindingContext.ModelName,
elementMetadata);
innerBindingContext.ValueProvider = new CompositeValueProvider
{
// our temporary provider goes at the front of the list
new ElementalValueProvider(bindingContext.ModelName, rawValueElement, culture),
bindingContext.ValueProvider
};
object boundValue = null;
var result =
await bindingContext.OperationBindingContext.ModelBinder.BindModelAsync(innerBindingContext);
if (result != null && result.IsModelSet)
{
boundValue = result.Model;
if (result.ValidationNode != null)
{
validationNode.ChildNodes.Add(result.ValidationNode);
}
}
boundCollection.Add(ModelBindingHelper.CastOrDefault <TElement>(boundValue));
}
return(new CollectionResult
{
ValidationNode = validationNode,
Model = boundCollection
});
}
internal async Task <IEnumerable <TElement> > BindComplexCollectionFromIndexes(ModelBindingContext bindingContext,
IEnumerable <string> indexNames)
{
bool indexNamesIsFinite;
if (indexNames != null)
{
indexNamesIsFinite = true;
}
else
{
indexNamesIsFinite = false;
indexNames = Enumerable.Range(0, Int32.MaxValue)
.Select(i => i.ToString(CultureInfo.InvariantCulture));
}
var metadataProvider = bindingContext.OperationBindingContext.MetadataProvider;
var elementMetadata = metadataProvider.GetMetadataForType(typeof(TElement));
var boundCollection = new List <TElement>();
foreach (var indexName in indexNames)
{
var fullChildName = ModelBindingHelper.CreateIndexModelName(bindingContext.ModelName, indexName);
var childBindingContext = ModelBindingContext.GetChildModelBindingContext(
bindingContext,
fullChildName,
elementMetadata);
var didBind = false;
object boundValue = null;
var modelType = bindingContext.ModelType;
var result = await bindingContext.OperationBindingContext.ModelBinder.BindModelAsync(childBindingContext);
if (result != null)
{
didBind = true;
boundValue = result.Model;
}
// infinite size collection stops on first bind failure
if (!didBind && !indexNamesIsFinite)
{
break;
}
boundCollection.Add(ModelBindingHelper.CastOrDefault <TElement>(boundValue));
}
return(boundCollection);
}
// Returned dictionary contains entries corresponding to properties against which binding was attempted. If
// binding failed, the entry's value will have IsModelSet == false. Binding is attempted for all elements of
// propertyMetadatas.
private async Task <IDictionary <ModelMetadata, ModelBindingResult> > BindPropertiesAsync(
ModelBindingContext bindingContext,
IEnumerable <ModelMetadata> propertyMetadatas)
{
var results = new Dictionary <ModelMetadata, ModelBindingResult>();
foreach (var propertyMetadata in propertyMetadatas)
{
var propertyModelName = ModelNames.CreatePropertyModelName(
bindingContext.ModelName,
propertyMetadata.BinderModelName ?? propertyMetadata.PropertyName);
var childContext = ModelBindingContext.GetChildModelBindingContext(
bindingContext,
propertyModelName,
propertyMetadata);
// ModelBindingContext.Model property values may be non-null when invoked via TryUpdateModel(). Pass
// complex (including collection) values down so that binding system does not unnecessarily recreate
// instances or overwrite inner properties that are not bound. No need for this with simple values
// because they will be overwritten if binding succeeds. Arrays are never reused because they cannot
// be resized.
//
// ModelMetadata.PropertyGetter is not null safe; use it only if Model is non-null.
if (bindingContext.Model != null &&
propertyMetadata.PropertyGetter != null &&
propertyMetadata.IsComplexType &&
!propertyMetadata.ModelType.IsArray)
{
childContext.Model = propertyMetadata.PropertyGetter(bindingContext.Model);
}
var result = await bindingContext.OperationBindingContext.ModelBinder.BindModelAsync(childContext);
if (result == null)
{
// Could not bind. Let ProcessResult() know explicitly.
result = new ModelBindingResult(model: null, key: propertyModelName, isModelSet: false);
}
results[propertyMetadata] = result;
}
return(results);
}
private async Task <ModelBindingResult> CreateAndPopulateDto(
ModelBindingContext bindingContext,
IEnumerable <ModelMetadata> propertyMetadatas)
{
// create a DTO and call into the DTO binder
var dto = new ComplexModelDto(bindingContext.ModelMetadata, propertyMetadatas);
var metadataProvider = bindingContext.OperationBindingContext.MetadataProvider;
var dtoMetadata = metadataProvider.GetMetadataForType(typeof(ComplexModelDto));
var childContext = ModelBindingContext.GetChildModelBindingContext(
bindingContext,
bindingContext.ModelName,
dtoMetadata);
childContext.Model = dto;
return(await bindingContext.OperationBindingContext.ModelBinder.BindModelAsync(childContext));
}
public async Task <ModelBindingResult> BindModelAsync(ModelBindingContext bindingContext)
{
if (bindingContext.ModelType != typeof(ComplexModelDto))
{
return(null);
}
ModelBindingHelper.ValidateBindingContext(bindingContext, typeof(ComplexModelDto), allowNullModel: false);
var dto = (ComplexModelDto)bindingContext.Model;
foreach (var propertyMetadata in dto.PropertyMetadata)
{
var propertyModelName = ModelNames.CreatePropertyModelName(
bindingContext.ModelName,
propertyMetadata.BinderModelName ?? propertyMetadata.PropertyName);
var propertyBindingContext = ModelBindingContext.GetChildModelBindingContext(
bindingContext,
propertyModelName,
propertyMetadata);
var modelBindingResult =
await bindingContext.OperationBindingContext.ModelBinder.BindModelAsync(propertyBindingContext);
if (modelBindingResult == null)
{
// Could not bind. Add a result so MutableObjectModelBinder will check for [DefaultValue].
dto.Results[propertyMetadata] =
new ModelBindingResult(model: null, key: propertyModelName, isModelSet: false);
}
else
{
dto.Results[propertyMetadata] = modelBindingResult;
}
}
return(new ModelBindingResult(dto, bindingContext.ModelName, isModelSet: true));
}
private async Task <bool> CanValueBindAnyModelProperties(MutableObjectBinderContext context)
{
// We want to check to see if any of the properties of the model can be bound using the value providers,
// because that's all that MutableObjectModelBinder can handle.
//
// However, because a property might specify a custom binding source ([FromForm]), it's not correct
// for us to just try bindingContext.ValueProvider.ContainsPrefixAsync(bindingContext.ModelName),
// because that may include ALL value providers - that would lead us to mistakenly create the model
// when the data is coming from a source we should use (ex: value found in query string, but the
// model has [FromForm]).
//
// To do this we need to enumerate the properties, and see which of them provide a binding source
// through metadata, then we decide what to do.
//
// If a property has a binding source, and it's a greedy source, then it's not
// allowed to come from a value provider, so we skip it.
//
// If a property has a binding source, and it's a non-greedy source, then we'll filter the
// the value providers to just that source, and see if we can find a matching prefix
// (see CanBindValue).
//
// If a property does not have a binding source, then it's fair game for any value provider.
//
// If any property meets the above conditions and has a value from valueproviders, then we'll
// create the model and try to bind it. OR if ALL properties of the model have a greedy source,
// then we go ahead and create it.
//
var isAnyPropertyEnabledForValueProviderBasedBinding = false;
foreach (var propertyMetadata in context.PropertyMetadata)
{
// This check will skip properties which are marked explicitly using a non value binder.
var bindingSource = propertyMetadata.BindingSource;
if (bindingSource == null || !bindingSource.IsGreedy)
{
isAnyPropertyEnabledForValueProviderBasedBinding = true;
var propertyModelName = ModelNames.CreatePropertyModelName(
context.ModelBindingContext.ModelName,
propertyMetadata.BinderModelName ?? propertyMetadata.PropertyName);
var propertyModelBindingContext = ModelBindingContext.GetChildModelBindingContext(
context.ModelBindingContext,
propertyModelName,
propertyMetadata);
// If any property can return a true value.
if (await CanBindValue(propertyModelBindingContext))
{
return(true);
}
}
}
if (!isAnyPropertyEnabledForValueProviderBasedBinding)
{
// Either there are no properties or all the properties are marked as
// a non value provider based marker.
// This would be the case when the model has all its properties annotated with
// a IBinderMetadata. We want to be able to create such a model.
return(true);
}
return(false);
}
/// <inheritdoc />
public override async Task <ModelBindingResult> BindModelAsync([NotNull] ModelBindingContext bindingContext)
{
var result = await base.BindModelAsync(bindingContext);
if (result == null || !result.IsModelSet)
{
// No match for the prefix at all.
return(result);
}
Debug.Assert(result.Model != null);
var model = (IDictionary <TKey, TValue>)result.Model;
if (model.Count != 0)
{
// ICollection<KeyValuePair<TKey, TValue>> approach was successful.
return(result);
}
var enumerableValueProvider = bindingContext.ValueProvider as IEnumerableValueProvider;
if (enumerableValueProvider == null)
{
// No IEnumerableValueProvider available for the fallback approach. For example the user may have
// replaced the ValueProvider with something other than a CompositeValueProvider.
return(result);
}
// Attempt to bind dictionary from a set of prefix[key]=value entries. Get the short and long keys first.
var keys = await enumerableValueProvider.GetKeysFromPrefixAsync(bindingContext.ModelName);
if (!keys.Any())
{
// No entries with the expected keys.
return(result);
}
// Update the existing successful but empty ModelBindingResult.
var metadataProvider = bindingContext.OperationBindingContext.MetadataProvider;
var valueMetadata = metadataProvider.GetMetadataForType(typeof(TValue));
var valueBindingContext = ModelBindingContext.GetChildModelBindingContext(
bindingContext,
bindingContext.ModelName,
valueMetadata);
var modelBinder = bindingContext.OperationBindingContext.ModelBinder;
var validationNode = result.ValidationNode;
foreach (var key in keys)
{
var dictionaryKey = ConvertFromString(key.Key);
valueBindingContext.ModelName = key.Value;
var valueResult = await modelBinder.BindModelAsync(valueBindingContext);
// Always add an entry to the dictionary but validate only if binding was successful.
model[dictionaryKey] = ModelBindingHelper.CastOrDefault <TValue>(valueResult?.Model);
if (valueResult != null && valueResult.IsModelSet)
{
validationNode.ChildNodes.Add(valueResult.ValidationNode);
}
}
return(result);
}