0

好的..所以我有一个界面,我在保存时将其传回控制器,看起来有点像这样(删除大部分只是为了让这个想法得到理解)。如果需要,我可以添加更多细节,但我不想让每个人都不知所措。

public interface IProjectElement
{        
    string Name { get; set; }
    int ElementTypeID { get; set; }
    ...
}
public class BaseProjectElement : IProjectElement
{

    public int ElementTypeID { get; set; }
    public string AdditionalInformation { get; set; }
    ... 
}    

然后我有几个接口的实现,但这里有一个例子......

public class SQLElement : BaseProjectElement
{
    public int? DatabasePlatformID { get; set; }
}

从 Global.asax 内部 - 开始

ModelBinders.Binders.Add(typeof(IProjectElement), new ProjectElementModelBinder());

所以这就是问题所在。下面的代码确定对象的类型并创建适当的对象。我认为发生的是,我可以看到所有值都在 bindingContent.ValueProvider 数据中发送,但有趣的是属性集合只列出了接口的值。base.CreateModel 将创建我需要的类型,但仅使用来自接口的数据填充对象。我可以用一些丑陋的代码来解决它,在我设置 DatabasePlatformID 的地方设置额外的属性,但是我的一些类有几个额外的属性。我可能在这里遗漏了一些明显的东西。像这样设置附加属性不是很容易维护。

public class ProjectElementModelBinder : DefaultModelBinder 
{
    protected override object CreateModel(ControllerContext controllerContext, ModelBindingContext bindingContext, Type modelType)
    {
        string modelName = bindingContext.ModelName;
        var elementType = (int)bindingContext.ValueProvider.GetValue(string.Format("{0}.ElementType", modelName)).ConvertTo(typeof(int));
        Type instantiationType = null;
        if (elementType == 1)
        {
            instantiationType = typeof(IISElement);
        }
        else if (elementType == 2)
        {
            instantiationType = typeof(SharePointElement);
        }
        else if (elementType == 3)
        {
            instantiationType = typeof(SQLElement);
        }
        else if (elementType == 12)
        {
            instantiationType = typeof(SharedElement);
        }
        else
        {
            instantiationType = typeof(BaseProjectElement);
        }
        var obj = base.CreateModel(controllerContext, bindingContext, instantiationType);
        if (elementType == 3)
        {
            PropertyInfo pi = obj.GetType().GetProperty("DatabasePlatformID");
            int databasePlatformID = (int)bindingContext.ValueProvider.GetValue(string.Format("{0}.DatabasePlatformID", modelName)).ConvertTo(typeof(int));
            pi.SetValue(obj, databasePlatformID, null);
        }
        return obj;
    }
}

请注意,我也尝试使用我在其他任何地方看到的代码来执行此操作,但我看到的情况更糟,对象根本没有被填充。

        var obj=Activator.CreateInstance(instantiationType);
        bindingContext.ModelMetadata = ModelMetadataProviders.Current.GetMetadataForType(null, instantiationType);
        bindingContext.ModelMetadata.Model = obj;
        return obj;

这是我的控制器

public ActionResult SaveElements(Guid projectID, List<IProjectElement> selectedElements, List<ProjectElementRelationshipsDAO> selectedRelationships)
    {
        using (ManagedHostingHelper helper = new ManagedHostingHelper())
        {
            BasePageViewModel viewModel = helper.SaveElements(projectID, selectedElements, selectedRelationships);
            return Json(new
            {
                ViewModel = viewModel,
                JsonRequestBehavior.AllowGet
            });
        } 
    }

最后,这里是调用控制器的 javascript。使用敲除.js ..

self.SaveElements = function () {
    var saveURL = new UrlHelper().SaveElements();
        data: ko.toJSON({ projectID: self.ProjectID(), selectedElements: self.SelectedElements(), selectedRelationships: self.SelectedRelationships() }),
        type: "post", contentType: "application/json",
        success: function (result) {
            if (result.ReturnStatus == true) {
                self.GoForward();
            }
            else { alert('error'); }
        }
    });
};

SelectedElements 是一个 knockout.js observableArray。下面是可以传递的 javascript 对象。请注意,此数组将包含实现 IProjectElement 的元素集合。我也没有显示所有不同的类型,但它们都有一组基本数据并添加其他属性.

// base class - see class diagram in folder as types should match this fairly closely
function BaseProjectElement(data) {
    var self = this;
    self.ProjectElementID = ko.observable(data.ProjectElementID);
    self.ElementName = ko.observable(data.ElementName);
    ... more properties
    self.BaseElementValidationGroup = ko.validatedObservable({
        Name: self.Name
    });
    self.IsBaseElementValid = ko.computed(function () {
        return self.BaseElementValidationGroup().errors().length == 0;
    });
};
function SQLElement(data) {
    var self = this;
    ko.utils.extend(self, new BaseProjectElement(data));
    self.DatabasePlatformID = ko.observable(data.DatabasePlatformID).extend({ required: { params: true, message: ' ' } });
    self.SQLElementValidationGroup = ko.validatedObservable({
        DatabasePlatformID: self.DatabasePlatformID
    });
    self.IsSQLElementValid = ko.computed(function () {
        return (self.SQLElementValidationGroup().errors().length == 0) && self.IsBaseElementValid();
    });
};
4

1 回答 1

0

好的..我以为我曾经做过类似的事情,但这对我有用.. ModelMetaData 的设置与我在几个地方看到的行,比如`

bindingContext.ModelMetadata = ModelMetadataProviders.Current.GetMetadataForType(null, instantiationType);

VS

public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
    {
        string modelName = bindingContext.ModelName;
        var elementType = (int)bindingContext.ValueProvider.GetValue(string.Format("{0}.ElementType", modelName)).ConvertTo(typeof(int));
        if (elementType == 1)
        {
            bindingContext.ModelMetadata = ModelMetadataProviders.Current.GetMetadataForType(() => new IISElement(), typeof(IISElement));
        }
        else if (elementType == 2)
        {
            bindingContext.ModelMetadata = ModelMetadataProviders.Current.GetMetadataForType(() => new SharePointElement(), typeof(SharePointElement));
        }
        else if (elementType == 3)
        {
            bindingContext.ModelMetadata = ModelMetadataProviders.Current.GetMetadataForType(() => new SQLElement(), typeof(SQLElement));
        }
        else if (elementType == 12)
        {
            bindingContext.ModelMetadata = ModelMetadataProviders.Current.GetMetadataForType(() => new SharedElement(), typeof(SharedElement));
        }
        else
        {
            bindingContext.ModelMetadata = ModelMetadataProviders.Current.GetMetadataForType(() => new BaseProjectElement(), typeof(BaseProjectElement));
        }
        return base.BindModel(controllerContext, bindingContext);
    }
于 2014-06-09T14:35:52.057 回答