Question

在我的ASP.Net MVC3项目中，我创建了一个绑定基本模型的ModelBinder。在我的View中，我从Model继承自我的basemodel创建了一个对象。现在我不知道当我按下提交按钮时，我的ModelBinder中通过反射创建了哪个模型，但是如何？

ModelBinder的：

public class MBTestBinder : IModelBinder
{
    public object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
    {
        //need to know which Model was created -> convert into the right object
        //reflection?
    }
}

型号：

[ModelBinder(typeof(MBTestBinder))]
public class MBTest
{
    public string Name { get; set; }
    public MBTest()  {}
}

public class MBAbl : MBTest
{
    public MBAbl()  {}
    public string House { get; set; }
}

查看：

@model ModelBinderProject.Models.MBTest

@using (Html.BeginForm("Index", "Home")) {
<fieldset>
    <div class="editor-field">
        @Html.EditorForModel(Model)
    </div>
    <p>
        <input type="submit" value="Create" />
    </p>
</fieldset>

控制器：

public ActionResult Create(MBTest testItem)
{
    //on init get a view from a class that hast inherit the class MBTest
    if (testItem.Name == null ) testItem = new MBAbl();

    return View(testItem);
}

编辑：

使用bindingContext.ValueProvider.GetValue("House")我可以获取表单的值，但bindingContext.ModelType认为我的模型是MBTest

Answer 1

查看ModelBindingContext文档。

根据评论编辑

public class MBTestBinder : IModelBinder
{
    public object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
    {
        var result = bindingContext.ValueProvider.GetValue("Name");

        if (result == null || string.IsNullOrEmpty(result.AttemptedValue))
           return new MBAbl();
        else
           return new MBTest();
    }
}

Answer 2

最后，我解决了它在我的模型中携带模型名称的变通方法，并在模型绑定器中动态创建了正确的模型。如果你知道一个更好的解决方案，请告诉我： - ）

HomeController中：

// CREATE
public ActionResult About(MBTest testItem)
{
    if (testItem == null)
    {
        testItem = new MBAbl();
        testItem.Model = "MBAbl";
    }

    return View(testItem);
}

型号：

public class MBTest
{
    public MBTest()  {}

    [HiddenInput]
    public string Model { get; set; }

    public string Name { get; set; }
}

public class MBAbl : MBTest
{
    public MBAbl()  {}

    public string House { get; set; }
}

public class MBAb2 : MBTest
{
    ...
}

ModelBinder的：

public object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
{
    if (controllerContext == null) throw new ArgumentNullException("controllerContext");
    if (bindingContext == null) throw new ArgumentNullException("bindingContext");

    //string 'Model' is needed in the base class
    var modelType = bindingContext.ValueProvider.GetValue("Model");

    if (modelType != null && !string.IsNullOrEmpty(modelType.AttemptedValue))
    {
        string projectName = System.Reflection.Assembly.GetExecutingAssembly().GetName().Name;

        Type classtype = Type.GetType(string.Format("{0}.Models.{1}", projectName, modelType.AttemptedValue));
        PropertyInfo[] properties = classtype.GetProperties();

        var classObject = classtype.GetConstructor(new Type[] { }).Invoke(null);

        foreach (PropertyInfo propertie in properties)
        {
            var value = bindingContext.ValueProvider.GetValue(propertie.Name).AttemptedValue;
            classtype.GetProperty(propertie.Name).SetValue(classObject, value, null);
        }

        return classObject;
    }
    return null;
}

Answer 3

试试这个：

public class ModelBinder : DefaultModelBinder, IModelBinder
{
    public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
    {
        var typeValue = bindingContext.ValueProvider.GetValue("ModelType");
        var type = Type.GetType("Namespace.a.b." + typeValue.AttemptedValue.ToString());

        var model = Activator.CreateInstance(type);

        //Change the model
        bindingContext.ModelMetadata = ModelMetadataProviders.Current.GetMetadataForType(() => model, type);
        bindingContext.ModelMetadata.Model = model;

        //Here, we used the default model binder of the mvc
        return base.BindModel(controllerContext, bindingContext);;
    }
}

如何将http请求转换为正确的对象？

3 个答案: