/// <summary>
/// Creates a new <see cref="ModelExplorer"/>.
/// </summary>
/// <param name="metadataProvider">The <see cref="IModelMetadataProvider"/>.</param>
/// <param name="container">The container <see cref="ModelExplorer"/>.</param>
/// <param name="metadata">The <see cref="ModelMetadata"/>.</param>
/// <param name="modelAccessor">A model accessor function. May be <c>null</c>.</param>
public ModelExplorer(
IModelMetadataProvider metadataProvider,
ModelExplorer container,
ModelMetadata metadata,
Func<object, object> modelAccessor)
{
if (metadataProvider == null)
{
throw new ArgumentNullException(nameof(metadataProvider));
}
if (container == null)
{
throw new ArgumentNullException(nameof(container));
}
if (metadata == null)
{
throw new ArgumentNullException(nameof(metadata));
}
_metadataProvider = metadataProvider;
Container = container;
Metadata = metadata;
_modelAccessor = modelAccessor;
}
public TemplateBuilder(
IViewEngine viewEngine,
IViewBufferScope bufferScope,
ViewContext viewContext,
ViewDataDictionary viewData,
ModelExplorer modelExplorer,
string htmlFieldName,
string templateName,
bool readOnly,
object additionalViewData)
{
if (viewEngine == null)
{
throw new ArgumentNullException(nameof(viewEngine));
}
if (bufferScope == null)
{
throw new ArgumentNullException(nameof(_bufferScope));
}
if (viewContext == null)
{
throw new ArgumentNullException(nameof(viewContext));
}
if (viewData == null)
{
throw new ArgumentNullException(nameof(viewData));
}
if (modelExplorer == null)
{
throw new ArgumentNullException(nameof(modelExplorer));
}
_viewEngine = viewEngine;
_bufferScope = bufferScope;
_viewContext = viewContext;
_viewData = viewData;
_modelExplorer = modelExplorer;
_htmlFieldName = htmlFieldName;
_templateName = templateName;
_readOnly = readOnly;
_additionalViewData = additionalViewData;
_model = modelExplorer.Model;
_metadata = modelExplorer.Metadata;
}
/// <summary>
/// Initializes a new instance of the <see cref="ModelExpression"/> class.
/// </summary>
/// <param name="name">
/// String representation of the <see cref="System.Linq.Expressions.Expression"/> of interest.
/// </param>
/// <param name="modelExplorer">
/// Includes the model and metadata about the <see cref="System.Linq.Expressions.Expression"/> of interest.
/// </param>
public ModelExpression(string name, ModelExplorer modelExplorer)
{
if (name == null)
{
throw new ArgumentNullException(nameof(name));
}
if (modelExplorer == null)
{
throw new ArgumentNullException(nameof(modelExplorer));
}
Name = name;
ModelExplorer = modelExplorer;
}
public static string GetModelErrorMessageOrDefault(
ModelError modelError,
ModelStateEntry containingEntry,
ModelExplorer modelExplorer)
{
Debug.Assert(modelError != null);
Debug.Assert(containingEntry != null);
Debug.Assert(modelExplorer != null);
if (!string.IsNullOrEmpty(modelError.ErrorMessage))
{
return modelError.ErrorMessage;
}
// Default in the ValidationMessage case is a fallback error message.
var attemptedValue = containingEntry.AttemptedValue ?? "null";
return modelExplorer.Metadata.ModelBindingMessageProvider.ValueIsInvalidAccessor(attemptedValue);
}
// Only render attributes if client-side validation is enabled, and then only if we've
// never rendered validation for a field with this name in this form.
protected override IDictionary<string, object> GetValidationAttributes(ViewContext viewContext, ModelExplorer modelExplorer, string expression) {
var formContext = viewContext.ClientValidationEnabled ? viewContext.FormContext : null;
if (formContext == null) {
return null;
}
var fullName = GetFullHtmlFieldName(viewContext, expression);
if (formContext.RenderedField(fullName)) {
return null;
}
formContext.RenderedField(fullName, true);
var clientRules = GetClientValidationRules(viewContext, modelExplorer, expression);
// use inbuilt Unobtrusive validation when the parsley attribute is not used
if (viewContext.ViewData.ContainsKey(ParsleyValidationAttributesGenerator.USE_PARSLEY_KEY)
&& (bool)viewContext.ViewData[ParsleyValidationAttributesGenerator.USE_PARSLEY_KEY] == true)
return ParsleyValidationAttributesGenerator.GetValidationAttributes(clientRules);
else
return UnobtrusiveValidationAttributesGenerator.GetValidationAttributes(clientRules);
}
public void ValidateSetsMemberNamePropertyOfValidationContextForProperties(
ModelExplorer modelExplorer,
string expectedMemberName)
{
// Arrange
var attribute = new Mock<ValidationAttribute> { CallBase = true };
attribute.Protected()
.Setup<ValidationResult>("IsValid", ItExpr.IsAny<object>(), ItExpr.IsAny<ValidationContext>())
.Callback((object o, ValidationContext context) =>
{
Assert.Equal(expectedMemberName, context.MemberName);
})
.Returns(ValidationResult.Success)
.Verifiable();
var validator = new DataAnnotationsModelValidator(attribute.Object);
var validationContext = CreateValidationContext(modelExplorer);
// Act
var results = validator.Validate(validationContext);
// Assert
Assert.Empty(results);
attribute.VerifyAll();
}
private TagBuilder GenerateTextBox(ModelExplorer modelExplorer, string inputTypeHint, string inputType)
{
var format = Format;
if (string.IsNullOrEmpty(format))
{
format = GetFormat(modelExplorer, inputTypeHint, inputType);
}
var htmlAttributes = new Dictionary<string, object>
{
{ "type", inputType }
};
if (string.Equals(inputType, "file") && string.Equals(inputTypeHint, TemplateRenderer.IEnumerableOfIFormFileName))
{
htmlAttributes["multiple"] = "multiple";
}
return Generator.GenerateTextBox(
ViewContext,
modelExplorer,
For.Name,
value: modelExplorer.Model,
format: format,
htmlAttributes: htmlAttributes);
}
private TagBuilder GenerateRadio(ModelExplorer modelExplorer)
{
// Note empty string is allowed.
if (Value == null)
{
throw new InvalidOperationException(Resources.FormatInputTagHelper_ValueRequired(
"<input>",
nameof(Value).ToLowerInvariant(),
"type",
"radio"));
}
return Generator.GenerateRadioButton(
ViewContext,
modelExplorer,
For.Name,
Value,
isChecked: null,
htmlAttributes: null);
}
private void GenerateCheckBox(ModelExplorer modelExplorer, TagHelperOutput output)
{
if (typeof(bool) != modelExplorer.ModelType)
{
throw new InvalidOperationException(Resources.FormatInputTagHelper_InvalidExpressionResult(
"<input>",
ForAttributeName,
modelExplorer.ModelType.FullName,
typeof(bool).FullName,
"type",
"checkbox"));
}
// Prepare to move attributes from current element to <input type="checkbox"/> generated just below.
var htmlAttributes = new Dictionary<string, object>(StringComparer.OrdinalIgnoreCase);
// Perf: Avoid allocating enumerator
// Construct attributes correctly (first attribute wins).
for (var i = 0; i < output.Attributes.Count; i++)
{
var attribute = output.Attributes[i];
if (!htmlAttributes.ContainsKey(attribute.Name))
{
htmlAttributes.Add(attribute.Name, attribute.Value);
}
}
var checkBoxTag = Generator.GenerateCheckBox(
ViewContext,
modelExplorer,
For.Name,
isChecked: null,
htmlAttributes: htmlAttributes);
if (checkBoxTag != null)
{
// Do not generate current element's attributes or tags. Instead put both <input type="checkbox"/> and
// <input type="hidden"/> into the output's Content.
output.Attributes.Clear();
output.TagName = null;
var renderingMode =
output.TagMode == TagMode.SelfClosing ? TagRenderMode.SelfClosing : TagRenderMode.StartTag;
checkBoxTag.TagRenderMode = renderingMode;
output.Content.AppendHtml(checkBoxTag);
var hiddenForCheckboxTag = Generator.GenerateHiddenForCheckbox(ViewContext, modelExplorer, For.Name);
if (hiddenForCheckboxTag != null)
{
hiddenForCheckboxTag.TagRenderMode = renderingMode;
if (ViewContext.FormContext.CanRenderAtEndOfForm)
{
ViewContext.FormContext.EndOfFormContent.Add(hiddenForCheckboxTag);
}
else
{
output.Content.AppendHtml(hiddenForCheckboxTag);
}
}
}
}
public static IEnumerable <IDictionary <string, object> > GetValidationRules(string propertyName, ModelExplorer modelExplorer, ViewContext viewContext)
{
List <IDictionary <string, object> > list = new List <IDictionary <string, object> >();
ModelMetadata modelMetadata = modelExplorer?.Metadata;
if (modelMetadata != null)
{
IDictionary <string, string> validationAttributes = GetValidationAttributes(viewContext, modelExplorer, propertyName);
{
foreach (KeyValuePair <string, string> item in validationAttributes)
{
string text = item.Key.Replace("data-val-", "");
bool flag = text.StartsWith("custom") && text.Split(new char[1]
{
'-'
}).Length == 2;
if ((validationTypesMap.ContainsKey(text) && !SkipValidationRule(text, modelMetadata)) | flag)
{
Dictionary <string, object> dictionary = new Dictionary <string, object>();
string text2 = "data-val-" + text + "-";
foreach (KeyValuePair <string, string> item2 in validationAttributes)
{
if (item2.Key.Contains(text2))
{
string text3 = item2.Key.Replace(text2, "");
object value = (text3 != "pattern") ? ((object)new JS(item2.Value)) : item2.Value;
dictionary.Add(text3, value);
}
}
text = (flag ? "custom" : text);
list.Add(CreateClientValidationRule(propertyName, text, item.Value, dictionary));
}
}
return(list);
}
}
return(list);
}
protected virtual bool IsRadioGroup(ModelExplorer explorer)
{
return(explorer.GetAttribute <AbpRadioButton>() != null);
}
private static ModelValidationContext CreateValidationContext(ModelExplorer modelExplorer)
{
return new ModelValidationContext(
bindingSource: null,
modelState: null,
validatorProvider: null,
modelExplorer: modelExplorer);
}
private bool ValidateElements(string currentKey, IEnumerable model, ValidationContext validationContext)
{
var elementType = GetElementType(model.GetType());
var elementMetadata = _modelMetadataProvider.GetMetadataForType(elementType);
var validatorProvider = validationContext.ModelValidationContext.ValidatorProvider;
var validatorProviderContext = new ModelValidatorProviderContext(elementMetadata);
validatorProvider.GetValidators(validatorProviderContext);
var validators = validatorProviderContext.Validators;
// If there are no validators or the object is null we bail out quickly
// when there are large arrays of null, this will save a significant amount of processing
// with minimal impact to other scenarios.
var anyValidatorsDefined = validators.Any();
var index = 0;
var isValid = true;
foreach (var element in model)
{
// If the element is non null, the recursive calls might find more validators.
// If it's null, then a shallow validation will be performed.
if (element != null || anyValidatorsDefined)
{
var elementExplorer = new ModelExplorer(_modelMetadataProvider, elementMetadata, element);
var elementKey = ModelBindingHelper.CreateIndexModelName(currentKey, index);
var elementValidationContext = new ValidationContext()
{
ModelValidationContext = ModelValidationContext.GetChildValidationContext(
validationContext.ModelValidationContext,
elementExplorer),
Visited = validationContext.Visited
};
if (!ValidateNonVisitedNodeAndChildren(elementKey, elementValidationContext, validators))
{
isValid = false;
}
}
index++;
}
return isValid;
}
private static bool ShouldShow(ModelExplorer modelExplorer, TemplateInfo templateInfo)
{
return
modelExplorer.Metadata.ShowForEdit &&
!modelExplorer.Metadata.IsComplexType &&
!templateInfo.Visited(modelExplorer);
}
protected virtual List <ModelExpression> ExploreModelsRecursively(List <ModelExpression> list, ModelExplorer model)
{
if (model.GetAttribute <DynamicFormIgnore>() != null)
{
return(list);
}
if (IsCsharpClassOrPrimitive(model.ModelType) || IsListOfCsharpClassOrPrimitive(model.ModelType))
{
list.Add(ModelExplorerToModelExpressionConverter(model));
return(list);
}
if (IsListOfSelectItem(model.ModelType))
{
return(list);
}
return(model.Properties.Aggregate(list, ExploreModelsRecursively));
}
// A variant of TemplateRenderer.GetViewNames(). Main change relates to bool? handling.
private static IEnumerable<string> GetInputTypeHints(ModelExplorer modelExplorer)
{
if (!string.IsNullOrEmpty(modelExplorer.Metadata.TemplateHint))
{
yield return modelExplorer.Metadata.TemplateHint;
}
if (!string.IsNullOrEmpty(modelExplorer.Metadata.DataTypeName))
{
yield return modelExplorer.Metadata.DataTypeName;
}
// In most cases, we don't want to search for Nullable<T>. We want to search for T, which should handle
// both T and Nullable<T>. However we special-case bool? to avoid turning an <input/> into a <select/>.
var fieldType = modelExplorer.ModelType;
if (typeof(bool?) != fieldType)
{
fieldType = modelExplorer.Metadata.UnderlyingOrModelType;
}
foreach (string typeName in TemplateRenderer.GetTypeNames(modelExplorer.Metadata, fieldType))
{
yield return typeName;
}
}
public IList<ModelExplorer> GetPropertiesForList(ModelExplorer explorer)
{
var metadata = explorer.Properties.Where(x => ((DefaultModelMetadata)x.Metadata).Attributes.PropertyAttributes.OfType<ShowListAttribute>().Any());
return metadata.ToList();
}
/// <summary>
/// Creates a new <see cref="ModelExplorer"/>.
/// </summary>
/// <param name="metadataProvider">The <see cref="IModelMetadataProvider"/>.</param>
/// <param name="container">The container <see cref="ModelExplorer"/>.</param>
/// <param name="metadata">The <see cref="ModelMetadata"/>.</param>
/// <param name="model">The model object. May be <c>null</c>.</param>
public ModelExplorer(
IModelMetadataProvider metadataProvider,
ModelExplorer container,
ModelMetadata metadata,
object model)
{
if (metadataProvider == null)
{
throw new ArgumentNullException(nameof(metadataProvider));
}
if (metadata == null)
{
throw new ArgumentNullException(nameof(metadata));
}
_metadataProvider = metadataProvider;
Container = container;
Metadata = metadata;
_model = model;
}
protected virtual bool IsEnum(ModelExplorer explorer)
{
return(explorer.Metadata.IsEnum);
}
// Get a fall-back format based on the metadata.
private string GetFormat(ModelExplorer modelExplorer, string inputTypeHint, string inputType)
{
string format;
string rfc3339Format;
if (string.Equals("decimal", inputTypeHint, StringComparison.OrdinalIgnoreCase) &&
string.Equals("text", inputType, StringComparison.Ordinal) &&
string.IsNullOrEmpty(modelExplorer.Metadata.EditFormatString))
{
// Decimal data is edited using an <input type="text"/> element, with a reasonable format.
// EditFormatString has precedence over this fall-back format.
format = "{0:0.00}";
}
else if (_rfc3339Formats.TryGetValue(inputType, out rfc3339Format) &&
ViewContext.Html5DateRenderingMode == Html5DateRenderingMode.Rfc3339 &&
!modelExplorer.Metadata.HasNonDefaultEditFormat &&
(typeof(DateTime) == modelExplorer.ModelType || typeof(DateTimeOffset) == modelExplorer.ModelType))
{
// Rfc3339 mode _may_ override EditFormatString in a limited number of cases e.g. EditFormatString
// must be a default format (i.e. came from a built-in [DataType] attribute).
format = rfc3339Format;
}
else
{
// Otherwise use EditFormatString, if any.
format = modelExplorer.Metadata.EditFormatString;
}
return format;
}
private static IDictionary <string, string> GetValidationAttributes(ViewContext viewContext, ModelExplorer modelExplorer, string propertyName)
{
Dictionary <string, string> dictionary = new Dictionary <string, string>();
viewContext.HttpContext.RequestServices.GetService <ValidationHtmlAttributeProvider>()?.AddValidationAttributes(viewContext, modelExplorer, dictionary);
return(dictionary);
}
private string GetInputType(ModelExplorer modelExplorer, out string inputTypeHint)
{
foreach (var hint in GetInputTypeHints(modelExplorer))
{
string inputType;
if (_defaultInputTypes.TryGetValue(hint, out inputType))
{
inputTypeHint = hint;
return inputType;
}
}
inputTypeHint = InputType.Text.ToString().ToLowerInvariant();
return inputTypeHint;
}
protected virtual bool AreSelectItemsProvided(ModelExplorer explorer)
{
return(explorer.GetAttribute <SelectItems>() != null);
}
private bool ValidateProperties(
string currentModelKey,
ModelExplorer modelExplorer,
ValidationContext validationContext)
{
var isValid = true;
foreach (var property in modelExplorer.Metadata.Properties)
{
var propertyExplorer = modelExplorer.GetExplorerForProperty(property.PropertyName);
var propertyMetadata = propertyExplorer.Metadata;
var propertyValidationContext = new ValidationContext()
{
ModelValidationContext = ModelValidationContext.GetChildValidationContext(
validationContext.ModelValidationContext,
propertyExplorer),
Visited = validationContext.Visited
};
var propertyBindingName = propertyMetadata.BinderModelName ?? propertyMetadata.PropertyName;
var childKey = ModelBindingHelper.CreatePropertyModelName(currentModelKey, propertyBindingName);
if (!ValidateNonVisitedNodeAndChildren(
childKey,
propertyValidationContext,
validators: null))
{
isValid = false;
}
}
return isValid;
}
protected override IDictionary<string, object> GetValidationAttributes(
ViewContext viewContext,
ModelExplorer modelExplorer,
string name)
{
return ValidationAttributes;
}
// Validates a single node (not including children)
// Returns true if validation passes successfully
private static bool ShallowValidate(
string modelKey,
ModelExplorer modelExplorer,
ValidationContext validationContext,
IList<IModelValidator> validators)
{
var isValid = true;
var modelState = validationContext.ModelValidationContext.ModelState;
var fieldValidationState = modelState.GetFieldValidationState(modelKey);
if (fieldValidationState == ModelValidationState.Invalid)
{
// Even if we have no validators it's possible that model binding may have added a
// validation error (conversion error, missing data). We want to still run
// validators even if that's the case.
isValid = false;
}
// When the are no validators we bail quickly. This saves a GetEnumerator allocation.
// In a large array (tens of thousands or more) scenario it's very significant.
if (validators == null || validators.Count > 0)
{
var modelValidationContext = ModelValidationContext.GetChildValidationContext(
validationContext.ModelValidationContext,
modelExplorer);
var modelValidationState = modelState.GetValidationState(modelKey);
// If either the model or its properties are unvalidated, validate them now.
if (modelValidationState == ModelValidationState.Unvalidated ||
fieldValidationState == ModelValidationState.Unvalidated)
{
foreach (var validator in validators)
{
foreach (var error in validator.Validate(modelValidationContext))
{
var errorKey = ModelBindingHelper.CreatePropertyModelName(modelKey, error.MemberName);
if (!modelState.TryAddModelError(errorKey, error.Message) &&
modelState.GetFieldValidationState(errorKey) == ModelValidationState.Unvalidated)
{
// If we are not able to add a model error
// for instance when the max error count is reached, mark the model as skipped.
modelState.MarkFieldSkipped(errorKey);
}
isValid = false;
}
}
}
}
if (isValid)
{
validationContext.ModelValidationContext.ModelState.MarkFieldValid(modelKey);
}
return isValid;
}
public void ModelSetter_SetNullableNonNull_UpdatesModelExplorer()
{
// Arrange
var metadataProvider = new EmptyModelMetadataProvider();
var metadata = metadataProvider.GetMetadataForType(typeof(bool?));
var explorer = new ModelExplorer(metadataProvider, metadata, model: null);
var viewData = new ViewDataDictionary(metadataProvider)
{
ModelExplorer = explorer,
};
// Act
viewData.Model = true;
// Assert
Assert.NotNull(viewData.ModelMetadata);
Assert.NotNull(viewData.ModelExplorer);
Assert.Same(metadata, viewData.ModelMetadata);
Assert.Same(metadata.ModelType, explorer.ModelType);
Assert.NotSame(explorer, viewData.ModelExplorer);
Assert.Equal(viewData.Model, viewData.ModelExplorer.Model);
var model = Assert.IsType<bool>(viewData.Model);
Assert.True(model);
}
public static IHtmlContent CollectionTemplate(IHtmlHelper htmlHelper)
{
var viewData = htmlHelper.ViewData;
var model = viewData.Model;
if (model == null)
{
return HtmlString.Empty;
}
var collection = model as IEnumerable;
if (collection == null)
{
// Only way we could reach here is if user passed templateName: "Collection" to an Editor() overload.
throw new InvalidOperationException(Resources.FormatTemplates_TypeMustImplementIEnumerable(
"Collection", model.GetType().FullName, typeof(IEnumerable).FullName));
}
var elementMetadata = htmlHelper.ViewData.ModelMetadata.ElementMetadata;
Debug.Assert(elementMetadata != null);
var typeInCollectionIsNullableValueType = elementMetadata.IsNullableValueType;
var serviceProvider = htmlHelper.ViewContext.HttpContext.RequestServices;
var metadataProvider = serviceProvider.GetRequiredService<IModelMetadataProvider>();
// Use typeof(string) instead of typeof(object) for IEnumerable collections. Neither type is Nullable<T>.
if (elementMetadata.ModelType == typeof(object))
{
elementMetadata = metadataProvider.GetMetadataForType(typeof(string));
}
var oldPrefix = viewData.TemplateInfo.HtmlFieldPrefix;
try
{
viewData.TemplateInfo.HtmlFieldPrefix = string.Empty;
var fieldNameBase = oldPrefix;
var result = new HtmlContentBuilder();
var viewEngine = serviceProvider.GetRequiredService<ICompositeViewEngine>();
var viewBufferScope = serviceProvider.GetRequiredService<IViewBufferScope>();
var index = 0;
foreach (var item in collection)
{
var itemMetadata = elementMetadata;
if (item != null && !typeInCollectionIsNullableValueType)
{
itemMetadata = metadataProvider.GetMetadataForType(item.GetType());
}
var modelExplorer = new ModelExplorer(
metadataProvider,
container: htmlHelper.ViewData.ModelExplorer,
metadata: itemMetadata,
model: item);
var fieldName = string.Format(CultureInfo.InvariantCulture, "{0}[{1}]", fieldNameBase, index++);
var templateBuilder = new TemplateBuilder(
viewEngine,
viewBufferScope,
htmlHelper.ViewContext,
htmlHelper.ViewData,
modelExplorer,
htmlFieldName: fieldName,
templateName: null,
readOnly: false,
additionalViewData: null);
result.AppendHtml(templateBuilder.Build());
}
return result;
}
finally
{
viewData.TemplateInfo.HtmlFieldPrefix = oldPrefix;
}
}
protected ViewDataDictionary(ViewDataDictionary source, object?model, Type declaredModelType)
: this(source._metadataProvider,
source.ModelState,
declaredModelType,
data : new CopyOnWriteDictionary <string, object?>(source, StringComparer.OrdinalIgnoreCase),
templateInfo : new TemplateInfo(source.TemplateInfo))
{
if (source == null)
{
throw new ArgumentNullException(nameof(source));
}
// A non-null Model must always be assignable to both _declaredModelType and ModelMetadata.ModelType.
//
// ModelMetadata.ModelType should also be assignable to _declaredModelType. Though corner cases exist such
// as a ViewDataDictionary<List<int>> holding information about an IEnumerable<int> property (because an
// @model directive matched the runtime type though the view's name did not), we'll throw away the property
// metadata in those cases -- preserving invariant that ModelType can be assigned to _declaredModelType.
//
// More generally, since defensive copies to base VDD and VDD<object> abound, it's important to preserve
// metadata despite _declaredModelType changes.
var modelType = model?.GetType();
var modelOrDeclaredType = modelType ?? declaredModelType;
if (source.ModelMetadata.MetadataKind == ModelMetadataKind.Type &&
source.ModelMetadata.ModelType == typeof(object) &&
modelOrDeclaredType != typeof(object))
{
// Base ModelMetadata on new type when there's no property information to preserve and type changes to
// something besides typeof(object).
ModelExplorer = _metadataProvider.GetModelExplorerForType(modelOrDeclaredType, model);
}
else if (!declaredModelType.IsAssignableFrom(source.ModelMetadata.ModelType))
{
// Base ModelMetadata on new type when existing metadata is incompatible with the new declared type.
ModelExplorer = _metadataProvider.GetModelExplorerForType(modelOrDeclaredType, model);
}
else if (modelType != null && !source.ModelMetadata.ModelType.IsAssignableFrom(modelType))
{
// Base ModelMetadata on new type when new model is incompatible with the existing metadata.
ModelExplorer = _metadataProvider.GetModelExplorerForType(modelType, model);
}
else if (object.ReferenceEquals(model, source.ModelExplorer.Model))
{
// Source's ModelExplorer is already exactly correct.
ModelExplorer = source.ModelExplorer;
}
else
{
// The existing metadata is compatible with the value and declared type but it's a new value.
ModelExplorer = new ModelExplorer(
_metadataProvider,
source.ModelExplorer.Container,
source.ModelMetadata,
model);
}
// Ensure the given Model is compatible with _declaredModelType. Do not do this one of the following
// special cases:
// - Constructing a ViewDataDictionary<TModel> where TModel is a non-Nullable value type. This may for
// example occur when activating a RazorPage<int> and the container is null.
// - Constructing a ViewDataDictionary<object> immediately before overwriting ModelExplorer with correct
// information. See TemplateBuilder.Build().
if (model != null)
{
EnsureCompatible(model);
}
}