MVC 学习随笔（一）

Model的绑定。

（一）使用NameValueCollectionValueProvider 

C# 对NameValueCollectionValueProvider的支持是通过下面的类实现的

// Library部分
 public class NameValueCollectionValueProvider : IUnvalidatedValueProvider, IValueProvider
{
// 构造函数
        public NameValueCollectionValueProvider(NameValueCollection collection, CultureInfo culture);
// 实现IValueProvider
    public virtual ValueProviderResult GetValue(string key);
// 省略
}
 
 [Serializable]
    public class ValueProviderResult
    {
        public object RawValue { get; protected set; }
        public object ConvertTo(Type type);
 
    }

下面介绍一个简单的应用

// 应用部分
//Controller中定义NameValueCollectionValueProvider 作为显示Model传递给View
  NameValueCollection collection = new NameValueCollection();
            collection.Add("bar.Name", "John");
            collection.Add("bar.Age", "12");
            collection.Add("bar.Address.Street", "HongKang Street");
            collection.Add("bar.Address.ZipCode", "021");
            NameValueCollectionValueProvider nProvider = new NameValueCollectionValueProvider(collection, CultureInfo.CurrentCulture);
            var test = nProvider.GetValue("bar.Name");
            return View(nProvider);
 

在View中接收来自Controller的传递

@Model NameValueCollectionValueProvider
 
<table>
        <tr>
            <th colspan="2">Bar</th>
        </tr>
        <tr>
            <td>bar.Name</td>
            <td>@Model.GetValue("bar.Name").ConvertTo(typeof(string))</td>
        </tr>
        <tr>
            <td>bar.Age</td>
            <td>@Model.GetValue("bar.Age").ConvertTo(typeof(string))</td>
        </tr>
 
        <tr>
            <th colspan="2">Bar.Address</th>
        </tr>
        <tr>
            <td>bar.Address.Street</td>
            <td>@Model.GetValue("bar.Address.Street").ConvertTo(typeof(string))</td>
        </tr>
        <tr>
            <td>bar.Address.ZipCode</td>
            <td>@Model.GetValue("bar.Address.ZipCode").ConvertTo(typeof(string))</td>
        </tr>
    </table>

继承自NameValueCollectionValueProvider的类有下面几个：

1.1： FormValueProvider 传递Form中控件的值

@using (Html.BeginForm("TestFormValueProvider", "Home", FormMethod.Post, new { enctype = "multipart/form-data" }))
    {
        <input type="text" name="testBox" value="" />
        <input type="submit" value="提交" title="提交" />
    }

在Controller中将获取Form中提交的控件值

 public ActionResult TestFormValueProvider() {
            FormValueProvider form = new FormValueProvider(ControllerContext);
            var testBoxValue = form.GetValue("testBox");
            var outPut = testBoxValue.ConvertTo(typeof(string));
            Console.WriteLine(outPut);
            return null;
        }

1.2： QueryStringValueProvider传递查询字符串

// HTML 代码片段 
  <a href="@Url.Action("TestQueryStringProvider", "Home", new { Name="John Shen", Age="32"})" title="actionTest">测试URL QueryString传递Model</a>

Controller中获取View中的<a></a>的查询字符串

public ActionResult TestQueryStringProvider()
        {
            QueryStringValueProvider query = new QueryStringValueProvider(ControllerContext);
            var testNameQueryString = query.GetValue("Name").ConvertTo(typeof(string));
            var testAgeQueryString = query.GetValue("Age").ConvertTo(typeof(string));
            var testCompanyQueryString = query.GetValue("Company").ConvertTo(typeof(string));
            Console.WriteLine(testNameQueryString.ToString() + testAgeQueryString.ToString() + testCompanyQueryString.ToString());
            return null;
        }

（二）使用DictionaryValueProvider传递Model

NameValueCollectionValueProvider的是一个不对Key进行唯一性约束的键值列表，并且其Value只能是字符串。而DictionaryValueProvider才是真正意义上的键值对。Key有唯一性约束、Value可以是任何之。继承自DictionaryValueProvider的子类有以下几种

2.1： HttpFileCollectionValueProvider上传文件的绑定

HTML：

 @using (Html.BeginForm("TestFormValueProvider", "Home", FormMethod.Post, new { enctype = "multipart/form-data" }))
    { 
        <input type="text" name="testBox" value="" />
        <input type="submit" value="提交" title="提交" />
        <input type="file" name="file1"/>
        <input type="file" name="file2"/>
        <input type="file" name="file3"/>
        <input type="file" name="file1"/>
    }

Controller中获取从Html中上传的文件

     HttpFileCollectionValueProvider files = new HttpFileCollectionValueProvider(ControllerContext);
            
            object test = files.GetValue("file1").ConvertTo(typeof(HttpPostedFileWrapper[]));
            var tes = test as HttpPostedFileWrapper[];

            foreach (var t in tes)
            {
                t.SaveAs(Server.MapPath("../Content") + "/"+t.FileName);
            }

因为文件上传控件中有两个Name是file1的。所以得到的是两个文件

　　

2.2： RouteDataValueProvider传递RouteData中的Values属性到View

        public ActionResult Index()
        {
            // Pass data in RouteDataDictionary 
            RouteDataValueProvider provider = new RouteDataValueProvider(ControllerContext);

            return View(provider);
        }

View中接收来自Controller的 Model

@Model RouteDataValueProvider
<h2>Index</h2>
<h3>@Model.GetValue("controller").ConvertTo(typeof(string))</h3>
<h3>@Model.GetValue("action").ConvertTo(typeof(string))</h3>

 2.3： ChildActionValueProvider传递RouteData中的Value到子Action中的View

MVC中有很多HTMLHelper的扩展方法用于生成当前View的子View

 // Summary:
    //     Represents support for calling child action methods and rendering the result
    //     inline in a parent view.
    public static class ChildActionExtensions
    {
        // Summary:
        //     Invokes the specified child action method and returns the result as an HTML
        //     string.
        //
        // Parameters:
        //   htmlHelper:
        //     The HTML helper instance that this method extends.
        //
        //   actionName:
        //     The name of the action method to invoke.
        //
        // Returns:
        //     The child action result as an HTML string.
        //
        // Exceptions:
        //   System.ArgumentNullException:
        //     The htmlHelper parameter is null.
        //
        //   System.ArgumentException:
        //     The actionName parameter is null or empty.
        //
        //   System.InvalidOperationException:
        //     The required virtual path data cannot be found.
        public static MvcHtmlString Action(this HtmlHelper htmlHelper, string actionName);
        //
        // Summary:
        //     Invokes the specified child action method with the specified parameters and
        //     returns the result as an HTML string.
        //
        // Parameters:
        //   htmlHelper:
        //     The HTML helper instance that this method extends.
        //
        //   actionName:
        //     The name of the action method to invoke.
        //
        //   routeValues:
        //     An object that contains the parameters for a route. You can use routeValues
        //     to provide the parameters that are bound to the action method parameters.
        //     The routeValues parameter is merged with the original route values and overrides
        //     them.
        //
        // Returns:
        //     The child action result as an HTML string.
        //
        // Exceptions:
        //   System.ArgumentNullException:
        //     The htmlHelper parameter is null.
        //
        //   System.ArgumentException:
        //     The actionName parameter is null or empty.
        //
        //   System.InvalidOperationException:
        //     The required virtual path data cannot be found.
        public static MvcHtmlString Action(this HtmlHelper htmlHelper, string actionName, object routeValues);
        //
        // Summary:
        //     Invokes the specified child action method using the specified parameters
        //     and returns the result as an HTML string.
        //
        // Parameters:
        //   htmlHelper:
        //     The HTML helper instance that this method extends.
        //
        //   actionName:
        //     The name of the action method to invoke.
        //
        //   routeValues:
        //     A dictionary that contains the parameters for a route. You can use routeValues
        //     to provide the parameters that are bound to the action method parameters.
        //     The routeValues parameter is merged with the original route values and overrides
        //     them.
        //
        // Returns:
        //     The child action result as an HTML string.
        //
        // Exceptions:
        //   System.ArgumentNullException:
        //     The htmlHelper parameter is null.
        //
        //   System.ArgumentException:
        //     The actionName parameter is null or empty.
        //
        //   System.InvalidOperationException:
        //     The required virtual path data cannot be found.
        public static MvcHtmlString Action(this HtmlHelper htmlHelper, string actionName, RouteValueDictionary routeValues);
        //
        // Summary:
        //     Invokes the specified child action method using the specified controller
        //     name and returns the result as an HTML string.
        //
        // Parameters:
        //   htmlHelper:
        //     The HTML helper instance that this method extends.
        //
        //   actionName:
        //     The name of the action method to invoke.
        //
        //   controllerName:
        //     The name of the controller that contains the action method.
        //
        // Returns:
        //     The child action result as an HTML string.
        //
        // Exceptions:
        //   System.ArgumentNullException:
        //     The htmlHelper parameter is null.
        //
        //   System.ArgumentException:
        //     The actionName parameter is null or empty.
        //
        //   System.InvalidOperationException:
        //     The required virtual path data cannot be found.
        public static MvcHtmlString Action(this HtmlHelper htmlHelper, string actionName, string controllerName);
        //
        // Summary:
        //     Invokes the specified child action method using the specified parameters
        //     and controller name and returns the result as an HTML string.
        //
        // Parameters:
        //   htmlHelper:
        //     The HTML helper instance that this method extends.
        //
        //   actionName:
        //     The name of the action method to invoke.
        //
        //   controllerName:
        //     The name of the controller that contains the action method.
        //
        //   routeValues:
        //     An object that contains the parameters for a route. You can use routeValues
        //     to provide the parameters that are bound to the action method parameters.
        //     The routeValues parameter is merged with the original route values and overrides
        //     them.
        //
        // Returns:
        //     The child action result as an HTML string.
        //
        // Exceptions:
        //   System.ArgumentNullException:
        //     The htmlHelper parameter is null.
        //
        //   System.ArgumentException:
        //     The actionName parameter is null or empty.
        //
        //   System.InvalidOperationException:
        //     The required virtual path data cannot be found.
        public static MvcHtmlString Action(this HtmlHelper htmlHelper, string actionName, string controllerName, object routeValues);
        //
        // Summary:
        //     Invokes the specified child action method using the specified parameters
        //     and controller name and returns the result as an HTML string.
        //
        // Parameters:
        //   htmlHelper:
        //     The HTML helper instance that this method extends.
        //
        //   actionName:
        //     The name of the action method to invoke.
        //
        //   controllerName:
        //     The name of the controller that contains the action method.
        //
        //   routeValues:
        //     A dictionary that contains the parameters for a route. You can use routeValues
        //     to provide the parameters that are bound to the action method parameters.
        //     The routeValues parameter is merged with the original route values and overrides
        //     them.
        //
        // Returns:
        //     The child action result as an HTML string.
        //
        // Exceptions:
        //   System.ArgumentNullException:
        //     The htmlHelper parameter is null.
        //
        //   System.ArgumentException:
        //     The actionName parameter is null or empty.
        //
        //   System.InvalidOperationException:
        //     The required virtual path data cannot be found.
        public static MvcHtmlString Action(this HtmlHelper htmlHelper, string actionName, string controllerName, RouteValueDictionary routeValues);
        //
        // Summary:
        //     Invokes the specified child action method and renders the result inline in
        //     the parent view.
        //
        // Parameters:
        //   htmlHelper:
        //     The HTML helper instance that this method extends.
        //
        //   actionName:
        //     The name of the child action method to invoke.
        //
        // Exceptions:
        //   System.ArgumentNullException:
        //     The htmlHelper parameter is null.
        //
        //   System.ArgumentException:
        //     The actionName parameter is null or empty.
        //
        //   System.InvalidOperationException:
        //     The required virtual path data cannot be found.
        public static void RenderAction(this HtmlHelper htmlHelper, string actionName);
        //
        // Summary:
        //     Invokes the specified child action method using the specified parameters
        //     and renders the result inline in the parent view.
        //
        // Parameters:
        //   htmlHelper:
        //     The HTML helper instance that this method extends.
        //
        //   actionName:
        //     The name of the child action method to invoke.
        //
        //   routeValues:
        //     An object that contains the parameters for a route. You can use routeValues
        //     to provide the parameters that are bound to the action method parameters.
        //     The routeValues parameter is merged with the original route values and overrides
        //     them.
        //
        // Exceptions:
        //   System.ArgumentNullException:
        //     The htmlHelper parameter is null.
        //
        //   System.ArgumentException:
        //     The actionName parameter is null or empty.
        //
        //   System.InvalidOperationException:
        //     The required virtual path data cannot be found.
        public static void RenderAction(this HtmlHelper htmlHelper, string actionName, object routeValues);
        //
        // Summary:
        //     Invokes the specified child action method using the specified parameters
        //     and renders the result inline in the parent view.
        //
        // Parameters:
        //   htmlHelper:
        //     The HTML helper instance that this method extends.
        //
        //   actionName:
        //     The name of the child action method to invoke.
        //
        //   routeValues:
        //     A dictionary that contains the parameters for a route. You can use routeValues
        //     to provide the parameters that are bound to the action method parameters.
        //     The routeValues parameter is merged with the original route values and overrides
        //     them.
        //
        // Exceptions:
        //   System.ArgumentNullException:
        //     The htmlHelper parameter is null.
        //
        //   System.ArgumentException:
        //     The actionName parameter is null or empty.
        //
        //   System.InvalidOperationException:
        //     The required virtual path data cannot be found.
        public static void RenderAction(this HtmlHelper htmlHelper, string actionName, RouteValueDictionary routeValues);
        //
        // Summary:
        //     Invokes the specified child action method using the specified controller
        //     name and renders the result inline in the parent view.
        //
        // Parameters:
        //   htmlHelper:
        //     The HTML helper instance that this method extends.
        //
        //   actionName:
        //     The name of the child action method to invoke.
        //
        //   controllerName:
        //     The name of the controller that contains the action method.
        //
        // Exceptions:
        //   System.ArgumentNullException:
        //     The htmlHelper parameter is null.
        //
        //   System.ArgumentException:
        //     The actionName parameter is null or empty.
        //
        //   System.InvalidOperationException:
        //     The required virtual path data cannot be found.
        public static void RenderAction(this HtmlHelper htmlHelper, string actionName, string controllerName);
        //
        // Summary:
        //     Invokes the specified child action method using the specified parameters
        //     and controller name and renders the result inline in the parent view.
        //
        // Parameters:
        //   htmlHelper:
        //     The HTML helper instance that this method extends.
        //
        //   actionName:
        //     The name of the child action method to invoke.
        //
        //   controllerName:
        //     The name of the controller that contains the action method.
        //
        //   routeValues:
        //     An object that contains the parameters for a route. You can use routeValues
        //     to provide the parameters that are bound to the action method parameters.
        //     The routeValues parameter is merged with the original route values and overrides
        //     them.
        //
        // Exceptions:
        //   System.ArgumentNullException:
        //     The htmlHelper parameter is null.
        //
        //   System.ArgumentException:
        //     The actionName parameter is null or empty.
        //
        //   System.InvalidOperationException:
        //     The required virtual path data cannot be found.
        public static void RenderAction(this HtmlHelper htmlHelper, string actionName, string controllerName, object routeValues);
        //
        // Summary:
        //     Invokes the specified child action method using the specified parameters
        //     and controller name and renders the result inline in the parent view.
        //
        // Parameters:
        //   htmlHelper:
        //     The HTML helper instance that this method extends.
        //
        //   actionName:
        //     The name of the child action method to invoke.
        //
        //   controllerName:
        //     The name of the controller that contains the action method.
        //
        //   routeValues:
        //     A dictionary that contains the parameters for a route. You can use routeValues
        //     to provide the parameters that are bound to the action method parameters.
        //     The routeValues parameter is merged with the original route values and overrides
        //     them.
        //
        // Exceptions:
        //   System.ArgumentNullException:
        //     The htmlHelper parameter is null.
        //
        //   System.ArgumentException:
        //     The actionName parameter is null or empty.
        //
        //   System.InvalidOperationException:
        //     The required virtual path data cannot be found.
        public static void RenderAction(this HtmlHelper htmlHelper, string actionName, string controllerName, RouteValueDictionary routeValues);
    }

首先定义一个View在它里面包含一个子的View(通过以上的扩展方法)

<div>
    @Html.Action("ChildActionMethod","Test", new {Name="John", Age="32"});
</div>

接着在他所指向的Controller中我们接收这个扩展方法的ChildActionValueProvider

  public ActionResult ChildActionMethod() {
            ChildActionValueProvider child = new ChildActionValueProvider(ControllerContext);

            return View(child);
        }

改Action方法指向的View就是子View中的内容

<h3>@Model.GetValue("Name").ConvertTo(typeof(string))</h3>

<h3>@Model.GetValue("Age").ConvertTo(typeof(string))</h3>

呈现的效果类似于：

 使用ValueProviderCollection传递Model。

Controller端代码

 NameValueCollection nCollection = new NameValueCollection() { };
            nCollection.Add("Name", "John");
            nCollection.Add("Age", "32");
            NameValueCollectionValueProvider provider1 = new NameValueCollectionValueProvider(nCollection,CultureInfo.CurrentCulture);

            Dictionary<string, string> routeData = new Dictionary<string, string>();
            routeData.Add("Controller", "MyController");
            routeData.Add("Action", "MyController");


            DictionaryValueProvider<string> provider2 = new DictionaryValueProvider<string>(routeData, CultureInfo.CurrentCulture);
            List<IValueProvider> providers = new List<IValueProvider>();
            providers.Add(provider1);
            providers.Add(provider2);


            ValueProviderCollection collection = new ValueProviderCollection(new List<IValueProvider>(providers));
            return View(collection);

View中可以使用Model.GetValue("...").ConvertTo(..)的方式获取ProviderCollection中传递过来的值。虽然该Collection中包含各种Provider的类型。但是ProviderCollection提供了类似于ValueProvider的GetValues方法。 他会从当前的所有Provider中找到第一个匹配的值。

反之从View中往Controller中的传值也是一样的。