/// <inheritdoc />
public override async Task BindModelAsync(ModelBindingContext bindingContext)
{
if (bindingContext == null)
{
throw new ArgumentNullException(nameof(bindingContext));
}
await base.BindModelAsync(bindingContext);
if (bindingContext.Result == null || !bindingContext.Result.Value.IsModelSet)
{
// No match for the prefix at all.
return;
}
var result = bindingContext.Result.Value;
Debug.Assert(result.Model != null);
var model = (IDictionary <TKey, TValue>)result.Model;
if (model.Count != 0)
{
// ICollection<KeyValuePair<TKey, TValue>> approach was successful.
return;
}
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;
}
// Attempt to bind dictionary from a set of prefix[key]=value entries. Get the short and long keys first.
var keys = enumerableValueProvider.GetKeysFromPrefix(bindingContext.ModelName);
if (!keys.Any())
{
// No entries with the expected keys.
return;
}
// Update the existing successful but empty ModelBindingResult.
var metadataProvider = bindingContext.OperationBindingContext.MetadataProvider;
var valueMetadata = metadataProvider.GetMetadataForType(typeof(TValue));
var modelBinder = bindingContext.OperationBindingContext.ModelBinder;
var keyMappings = new Dictionary <string, TKey>(StringComparer.Ordinal);
foreach (var kvp in keys)
{
// Use InvariantCulture to convert the key since ExpressionHelper.GetExpressionText() would use
// that culture when rendering a form.
var convertedKey = ModelBindingHelper.ConvertTo <TKey>(kvp.Key, culture: null);
using (bindingContext.EnterNestedScope(
modelMetadata: valueMetadata,
fieldName: bindingContext.FieldName,
modelName: kvp.Value,
model: null))
{
await modelBinder.BindModelAsync(bindingContext);
var valueResult = bindingContext.Result;
// Always add an entry to the dictionary but validate only if binding was successful.
model[convertedKey] = ModelBindingHelper.CastOrDefault <TValue>(valueResult.Value.Model);
keyMappings.Add(kvp.Key, convertedKey);
}
}
bindingContext.ValidationState.Add(model, new ValidationStateEntry()
{
Strategy = new ShortFormDictionaryValidationStrategy <TKey, TValue>(keyMappings, valueMetadata),
});
}
// Internal for testing.
internal async Task <CollectionResult> BindComplexCollectionFromIndexes(
ModelBindingContext bindingContext,
IEnumerable <string> indexNames)
{
bool indexNamesIsFinite;
if (indexNames != null)
{
indexNamesIsFinite = true;
}
else
{
indexNamesIsFinite = false;
indexNames = Enumerable.Range(0, int.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 = ModelNames.CreateIndexModelName(bindingContext.ModelName, indexName);
var didBind = false;
object boundValue = null;
ModelBindingResult?result;
using (bindingContext.EnterNestedScope(
elementMetadata,
fieldName: indexName,
modelName: fullChildName,
model: null))
{
await bindingContext.OperationBindingContext.ModelBinder.BindModelAsync(bindingContext);
result = bindingContext.Result;
}
if (result != null && result.Value.IsModelSet)
{
didBind = true;
boundValue = result.Value.Model;
}
// infinite size collection stops on first bind failure
if (!didBind && !indexNamesIsFinite)
{
break;
}
boundCollection.Add(ModelBindingHelper.CastOrDefault <TElement>(boundValue));
}
return(new CollectionResult
{
Model = boundCollection,
// If we're working with a fixed set of indexes then this is the format like:
//
// ?parameter.index=zero,one,two¶meter[zero]=0&¶meter[one]=1¶meter[two]=2...
//
// We need to provide this data to the validation system so it can 'replay' the keys.
// But we can't just set ValidationState here, because it needs the 'real' model.
ValidationStrategy = indexNamesIsFinite ?
new ExplicitIndexCollectionValidationStrategy(indexNames) :
null,
});
}
