asp.net-mvc – DataAnnotationsModelBinder如何使用自定义ViewM

我最终修改了DataAnnotationsModelBinder上的BindProperty来绕过NullReferenceException,我个人不喜欢只有绑定它们才有效(见下面的原因).

protected override void BindProperty(ControllerContext controllerContext,ModelBindingContext bindingContext,PropertyDescriptor propertyDescriptor) {
    string fullPropertyKey = CreateSubPropertyName(bindingContext.ModelName,propertyDescriptor.Name);

    // Only bind properties that are part of the request
    if (bindingContext.ValueProvider.DoesAnyKeyHavePrefix(fullPropertyKey)) {
        var innerContext = new ModelBindingContext() {
            Model = propertyDescriptor.GetValue(bindingContext.Model),ModelName = fullPropertyKey,ModelState = bindingContext.ModelState,ModelType = propertyDescriptor.PropertyType,ValueProvider = bindingContext.ValueProvider
        };

        IModelBinder binder = Binders.GetBinder(propertyDescriptor.PropertyType);
        object newPropertyValue = ConvertValue(propertyDescriptor,binder.BindModel(controllerContext,innerContext));
        ModelState modelState = bindingContext.ModelState[fullPropertyKey];
        if (modelState == null)
        {
            var keys = bindingContext.ValueProvider.FindKeysWithPrefix(fullPropertyKey);
            if (keys != null && keys.Count() > 0)
                modelState = bindingContext.ModelState[keys.First().Key];
        }
        // Only validate and bind if the property itself has no errors
        //if (modelState.Errors.Count == 0) {
            SetProperty(controllerContext,bindingContext,propertyDescriptor,newPropertyValue);
            if (OnPropertyValidating(controllerContext,newPropertyValue)) {

                OnPropertyValidated(controllerContext,newPropertyValue);
            }
        //}

        // There was an error getting the value from the binder,which was probably a format
        // exception (meaning,the data wasn't appropriate for the field)
        if (modelState.Errors.Count != 0) {
            foreach (var error in modelState.Errors.Where(err => err.ErrorMessage == "" && err.Exception != null).ToList()) {
                for (var exception = error.Exception; exception != null; exception = exception.InnerException) {
                    if (exception is FormatException) {
                        string displayName = GetDisplayName(propertyDescriptor);
                        string errorMessage = InvalidValueFormatter(propertyDescriptor,modelState.Value.AttemptedValue,displayName);
                        modelState.Errors.Remove(error);
                        modelState.Errors.Add(errorMessage);
                        break;
                    }
                }
            }
        }
    }
}

我也对它进行了修改,以便它始终绑定属性上的数据,无论它是否有效.这样我就可以将模型传递回视图,而无需将无效属性重置为null.

控制器摘录

[AcceptVerbs(HttpVerbs.Post)]
public ActionResult Edit(ProfileViewDataModel model)
{
    FormCollection form = new FormCollection(this.Request.Form);
    wsPerson service = new wsPerson();
    Person newPerson = service.Select(1,-1);
    if (ModelState.IsValid && TryUpdateModel<IPersonBindable>(newPerson,"Person",form.ToValueProvider()))
    {
        //call wsPerson.save(newPerson);
    }
    return View(model); //model.Person is always bound no null properties (unless they were null to begin with)
}

我的Model类(Person)来自web服务,所以我不能直接将属性放在它们上面,我解决这个问题的方法如下：

嵌套DataAnnotations的示例

[Validation.MetadataType(typeof(PersonValidation))]
public partial class Person : IPersonBindable { } //force partial.

public class PersonValidation
{
    [Validation.Immutable]
    public int Id { get; set; }
    [Validation.Required]
    public string FirstName { get; set; }
    [Validation.StringLength(35)]
    [Validation.Required]
    public string LastName { get; set; }
    CategoryItemNullable NearestGeographicRegion { get; set; }
}

[Validation.MetadataType(typeof(CategoryItemNullableValidation))]
public partial class CategoryItemNullable { }

public class CategoryItemNullableValidation
{
    [Validation.Required]
    public string Text { get; set; }
    [Validation.Range(1,10)]
    public string Value { get; set; }
}

现在,如果我将表单字段绑定到[ViewDataModel.] Person.NearestGeographicRegion.Text& [ViewDataModel.] Person.NearestGeographicRegion.Value ModelState开始正确验证它们,DataAnnotationsModelBinder也正确绑定它们.

这个答案不是决定性的,它是今天下午挠头的产物.
它没有经过适当的测试,尽管它已经通过了the project布莱恩威尔逊开始的单元测试,并且我自己进行了大部分有限的测试.为了真正关闭这个问题,我很想听听Brad Wilson关于这个解决方案的想法.