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,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>

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") %> 

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"]) %>
 

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"]);
    }
%>
:
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

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>

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