ASP.NET MVC学习笔记-Controller与View传值

在asp.net2.0的网页开发模式下，我们一般通过直将访问页面控件， 将值写入到页面， 但在Asp.net MVC模式下，已不能在Controller中再去访问页面控件了，要如何才能给View页面传值呢？

在Controller中有两个字典(ViewData和TempData)来实现View之间的值传递, 在ControllerBase类声明中我们就可以看到：

namespace System.Web.Mvc
{
    // 摘要:
    //     Represents the base class for all MVC controllers.
    public abstract class ControllerBase : MarshalByRefObject, IController
    {
        protected ControllerBase();
        // 摘要:
        //     Gets or sets the controller context.
        public ControllerContext ControllerContext { get; set; }
        //
        // 摘要:
        //     Gets or sets the temporary data.
        public TempDataDictionary TempData { get; set; }
        //
        // 摘要:
        //     Gets or sets a value indicating whether the request is valid.
        public bool ValidateRequest { get; set; }
        //
        // 摘要:
        //     Gets or sets the value provider.
        public IDictionary<string, ValueProviderResult> ValueProvider { get; set; }
        //
        // 摘要:
        //     Gets or sets the view data.
        public ViewDataDictionary ViewData { get; set; }
        // 摘要:
        //     Executes the specified request context.
        //
        // ���:
        //   requestContext:
        //     The request context.
        protected virtual void Execute(RequestContext requestContext);
        //
        // 摘要:
        //     Executes the core.
        protected abstract void ExecuteCore();
        //
        // 摘要:
        //     Initializes the specified request context.
        //
        // ���:
        //   requestContext:
        //     The request context.
        protected virtual void Initialize(RequestContext requestContext);
    }
}

namespace System.Web.Mvc { // 摘要: // Represents the base class for all MVC controllers. public abstract class ControllerBase : MarshalByRefObject, IController { protected ControllerBase(); // 摘要: // Gets or sets the controller context. public ControllerContext ControllerContext { get; set; } // // 摘要: // Gets or sets the temporary data. public TempDataDictionary TempData { get; set; } // // 摘要: // Gets or sets a value indicating whether the request is valid. public bool ValidateRequest { get; set; } // // 摘要: // Gets or sets the value provider. public IDictionary<string, ValueProviderResult> ValueProvider { get; set; } // // 摘要: // Gets or sets the view data. public ViewDataDictionary ViewData { get; set; } // 摘要: // Executes the specified request context. // // ���: // requestContext: // The request context. protected virtual void Execute(RequestContext requestContext); // // 摘要: // Executes the core. protected abstract void ExecuteCore(); // // 摘要: // Initializes the specified request context. // // ���: // requestContext: // The request context. protected virtual void Initialize(RequestContext requestContext); } } 

而在ViewResultBase中我们同样可以看到它也含有这两个字典存在:

// 摘要:
//     Base class used to supply the model to the view and then render the view
//     to the response.
public abstract class ViewResultBase : ActionResult
{
    protected ViewResultBase();
    // 摘要:
    //     Gets or sets the System.Web.Mvc.TempDataDictionary for this result.
    public TempDataDictionary TempData { get; set; }
    //
    // 摘要:
    //     Gets or sets the System.Web.Mvc.IView that is rendered to the response.
    public IView View { get; set; }
    //
    // 摘要:
    //     Gets or sets the view data System.Web.Mvc.ViewDataDictionary for this result.
    public ViewDataDictionary ViewData { get; set; }
    //
    // 摘要:
    //     Gets or sets the view engines (System.Web.Mvc.ViewEngineCollection) associated
    //     with this result.
    public ViewEngineCollection ViewEngineCollection { get; set; }
    //
    // 摘要:
    //     Gets or sets the name of the view to be rendered.
    public string ViewName { get; set; }
    // 摘要:
    //     When called by the action invoker, renders the view to the response.
    //
    // ���:
    //   context:
    //     The context within which the result is executed.
    public override void ExecuteResult(ControllerContext context);
    //
    // 摘要:
    //     When overridden, returns the System.Web.Mvc.ViewEngineResult used to render
    //     the view.
    //
    // ���:
    //   context:
    //     The context.
    //
    // �骰�:
    //     The view engine.
    protected abstract ViewEngineResult FindView(ControllerContext context);
}

// 摘要: // Base class used to supply the model to the view and then render the view // to the response. public abstract class ViewResultBase : ActionResult { protected ViewResultBase(); // 摘要: // Gets or sets the System.Web.Mvc.TempDataDictionary for this result. public TempDataDictionary TempData { get; set; } // // 摘要: // Gets or sets the System.Web.Mvc.IView that is rendered to the response. public IView View { get; set; } // // 摘要: // Gets or sets the view data System.Web.Mvc.ViewDataDictionary for this result. public ViewDataDictionary ViewData { get; set; } // // 摘要: // Gets or sets the view engines (System.Web.Mvc.ViewEngineCollection) associated // with this result. public ViewEngineCollection ViewEngineCollection { get; set; } // // 摘要: // Gets or sets the name of the view to be rendered. public string ViewName { get; set; } // 摘要: // When called by the action invoker, renders the view to the response. // // ���: // context: // The context within which the result is executed. public override void ExecuteResult(ControllerContext context); // // 摘要: // When overridden, returns the System.Web.Mvc.ViewEngineResult used to render // the view. // // ���: // context: // The context. // // �骰�: // The view engine. protected abstract ViewEngineResult FindView(ControllerContext context); }

由此可以看出,Controller通过ViewData,TempData传通到ViewResult中， 然后再由ViewResult传递到ViewPage中来实现值传递的。

1.TempData和ViewData的应用

ViewData只对当前Action有效，而TempData有点类似于Session, 可在所有View访问， 一般用于记录错误信息.

Action代码:

public ActionResult Index()
{
    ViewData["Message"] = "Welcome to ASP.NET MVC!";
    return View();
}

public ActionResult Index() { ViewData["Message"] = "Welcome to ASP.NET MVC!"; return View(); }

页面代码：

<h2><%= Html.Encode(ViewData["Message"]) %></h2>

<h2><%= Html.Encode(ViewData["Message"]) %></h2>
TempData使用方式与View使用方式一致.

2. ViewData与TextBox实现自动绑定

利用HtmlHelper创建TextBox时，使用名称与ViewData中的Key一致， 就会自动实现值绑定,如:

Name:<%= Html.TextBox("name") %>

Name:<%= Html.TextBox("name") %>

名称不相同的情况下，也可以利用TextBox的重载传值:

Name:<%= Html.TextBox("name", ViewData["Nm"]) %>

Name:<%= Html.TextBox("name", ViewData["Nm"]) %>

3.View向Controller传值

1). 利用Action参数

<form name="form1" action="/Home/Index" method="post">
    Name:<input type="text" name="name" /><br />
    Sex: <input type="text" name="sex" />
    <input type="submit" value="submit" />
</form>
<%
    if (ViewData["name"] != null)
    {
        Response.Write("your name is:" + ViewData["name"] + ",  your sex is:" + ViewData["sex"]);
    }
%>
:
public ActionResult Index(string name, string sex)
{
    ViewData["Message"] = "Welcome to ASP.NET MVC!";
    ViewData["name"] = name;
    ViewData["sex"] = sex;
    return View();
}

<form name="form1" action="/Home/Index" method="post"> Name:<input type="text" name="name" /><br /> Sex: <input type="text" name="sex" /> <input type="submit" value="submit" /> </form> <% if (ViewData["name"] != null) { Response.Write("your name is:" + ViewData["name"] + ", your sex is:" + ViewData["sex"]); } %> Action代码: public ActionResult Index(string name, string sex) { ViewData["Message"] = "Welcome to ASP.NET MVC!"; ViewData["name"] = name; ViewData["sex"] = sex; return View(); }

2).利用Request.From或Request.QueryString

public ActionResult Index()
{
    ViewData["Message"] = "Welcome to ASP.NET MVC!";
    ViewData["name"] = Request.Form["name"];
    ViewData["sex"] = Request.Form["sex"];
    return View();
}

public ActionResult Index() { ViewData["Message"] = "Welcome to ASP.NET MVC!"; ViewData["name"] = Request.Form["name"]; ViewData["sex"] = Request.Form["sex"]; return View(); }

3). 利用FormCollection获取页面值

public ActionResult Index(FormCollection form)
{
    ViewData["Message"] = "Welcome to ASP.NET MVC!";
    User u=new User();
    u.Name = form["Name"];
    u.Password = form["Password"];
    return View(u);
}

public ActionResult Index(FormCollection form) { ViewData["Message"] = "Welcome to ASP.NET MVC!"; User u=new User(); u.Name = form["Name"]; u.Password = form["Password"]; return View(u); }

4.传递强类型

1).添加一个传递强类型Model的Action

public ActionResult ModelDemo()
        {
            User u= new User() { UserName="li", Password="abcde" };
            return View(u);
        }

public ActionResult ModelDemo() { User u= new User() { UserName="li", Password="abcde" }; return View(u); }

对应的View也需要继随于ViewPage<User>, 对应代码如下:

<p>
<%User u = (User)ViewData.Model;%>
            UserName:
            <%= Html.Encode(u.UserName) %>
        </p>
        <p>
            Password:
            <%= Html.Encode(u.Password) %>
        </p