/// <inheritdoc />
public Task BindModelAsync(ModelBindingContext bindingContext)
{
if (bindingContext == null)
{
throw new ArgumentNullException(nameof(bindingContext));
}
// This method is optimized to use cached tasks when possible and avoid allocating
// using Task.FromResult or async state machines.
var modelType = bindingContext.ModelType;
if (modelType != typeof(IFormFile) && !typeof(IEnumerable <IFormFile>).IsAssignableFrom(modelType))
{
// Not a type this model binder supports. Let other binders run.
return(TaskCache.CompletedTask);
}
var createFileCollection = modelType == typeof(IFormFileCollection) &&
!bindingContext.ModelMetadata.IsReadOnly;
if (!createFileCollection && !ModelBindingHelper.CanGetCompatibleCollection <IFormFile>(bindingContext))
{
// Silently fail and stop other model binders running if unable to create an instance or use the
// current instance.
bindingContext.Result = ModelBindingResult.Failed(bindingContext.ModelName);
return(TaskCache.CompletedTask);
}
ICollection <IFormFile> postedFiles;
if (createFileCollection)
{
postedFiles = new List <IFormFile>();
}
else
{
postedFiles = ModelBindingHelper.GetCompatibleCollection <IFormFile>(bindingContext);
}
return(BindModelCoreAsync(bindingContext, postedFiles));
}
private static object GetCompatibleCollection(ModelBindingContext bindingContext, string[] values)
{
// Almost-always success if IsTopLevelObject.
if (!bindingContext.IsTopLevelObject && values.Length == 0)
{
return(null);
}
if (bindingContext.ModelType.IsAssignableFrom(typeof(string[])))
{
// Array we already have is compatible.
return(values);
}
var collection = ModelBindingHelper.GetCompatibleCollection <string>(bindingContext, values.Length);
for (int i = 0; i < values.Length; i++)
{
collection.Add(values[i]);
}
return(collection);
}
