Question

确定我遇到了MVC的问题，我将控制器/视图附加到多个模型，其中包含字符串的受保护内部集。在创建这些对象时，我需要能够设置字符串。说完了，我在理解ModelBinding方面遇到了问题。我为ModelBinder附加了一个非常基本的设置，但不知道从哪里开始：

/// <summary>
/// Handles binding for the string variables
/// </summary>
public class ActionResultModelBinder : DefaultModelBinder, IModelBinder, ITypedModelBinder
{
    #region Properties

    /// <summary>
    /// Gets the type that this model binder's associated with
    /// </summary>
    /// <value>
    /// The type that this model binder's associated with.
    /// </value>
    public Type AssociatedType
    {
        get
        {
           return typeof(string);
        }
    }

    #endregion Properties

    #region Methods

    /// <summary>
    /// Binds the model by using the specified controller context and binding context.
    /// </summary>
    /// <param name="controllerContext">The context within which the controller operates. The context information includes the controller, HTTP content, request context, and route data.</param>
    /// <param name="bindingContext">The context within which the model is bound. The context includes information such as the model object, model name, model type, property filter, and value provider.</param>
    /// <returns>
    /// The bound object.
    /// </returns>
    /// <exception cref="T:System.ArgumentNullException">The <paramref name="bindingContext "/>parameter is null.</exception>
    public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
    {
        var boundValue = base.BindModel(controllerContext, bindingContext);
        return bindingContext.ModelType == typeof(string);
    }

    /// <summary>
    /// Sets the specified property by using the specified controller context, binding context, and property value.
    /// </summary>
    /// <param name="controllerContext">The context within which the controller operates. The context information includes the controller, HTTP content, request context, and route data.</param>
    /// <param name="bindingContext">The context within which the model is bound. The context includes information such as the model object, model name, model type, property filter, and value provider.</param>
    /// <param name="propertyDescriptor">Describes a property to be set. The descriptor provides information such as the component type, property type, and property value. It also provides methods to get or set the property value.</param>
    /// <param name="value">The value to set for the property.</param>
    protected override void SetProperty(ControllerContext controllerContext, ModelBindingContext bindingContext, PropertyDescriptor propertyDescriptor, object value)
    {
        if (propertyDescriptor.PropertyType == typeof(string))
        {
            var stringVal = value as string;
        }

        base.SetProperty(controllerContext, bindingContext, propertyDescriptor, value);
    }

    #endregion Methods
}

Answer 1

好的，让我解释一下。

您希望绑定模型，因此首先需要在

中返回该模型

public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)

这是绑定名为FacebookGroupViewModel的模型的自定义绑定器的示例：

public class FacebookGroupViewModelBinder : IModelBinder
    {
        public object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
        {
            var model = new FacebookGroupViewModel();
            if(controllerContext.HttpContext.Request.Form.AllKeys.Contains("Friends"))
            {
                var friends = controllerContext.HttpContext.Request.Form["Friends"].Split(',');
                foreach (var friend in friends)
                {
                    model.FacebookFriendIds.Add(friend);
                }


 }
            return model;
        }
    }

在这里你可以看到我从表单中获取了一个值：

controllerContext.HttpContext.Request.Form["Friends"]

但你可以从QueryString或任何你想要的东西中获取值，因为你在这里有HttpContext。调试并查看您需要了解的所有属性。

最后，你需要设置这个绑定器，并通过这种方式将它与global.asax中的模型相关联。

ModelBinders.Binders.Add(typeof(FacebookGroupViewModel),new FacebookGroupViewModelBinder());

在应用程序启动方法中。

然后只使用想象一下，我的控制器是这样的。

[HttpPost]
public ActionResult PostFriend(FacebookGroupViewModel model)
{
//here your model is binded by your custom model ready to use.
}

完成工作，如果您对此有更多疑问，请与我联系。

您不需要的更多信息：

 protected override void SetProperty(ControllerContext controllerContext, ModelBindingContext bindingContext, PropertyDescriptor propertyDescriptor, object value)

允许您使用默认绑定器行为并覆盖某些属性，就像您只使用字符串一样，但为此您需要使用原始的bindModel方法。（例如base.BindModel）

模型MVC中的绑定字符串字段

1 个答案: