MVC懷疑視圖和控制器之間沒有數據傳遞

Question

我是MVC的新手，很困惑。正在使用不同顯示頁面的兩個主視圖，Index和DisplayPrediction。我嘗試使用數據註釋來驗證提交表單中的數據，但它只顯示錯誤消息，並且不會阻止加載第二個視圖。然而，最大的問題是，當第一個視圖返回時，輸入到文本框中的信息似乎簡單地重置爲默認值。幫助將非常感謝:)這是我現在的代碼：

這是模型，我保留需要從用戶那裏得到的字段，以及程序的功能（字段上的處理將生成應在所述第二視圖中顯示的輸出）：

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Web; 
using System.IO; 
using System.Diagnostics; 
using System.ComponentModel.DataAnnotations; 
using System.Web.Mvc; 
using System.ComponentModel; 

namespace MvcHaberman.Models 
{ 
public class HabermanPrediction 
{ 
    [Required] 
    [Range(0,100)] 
    public int age { set; get; } 
    [Required] 
    [Range(58, 69)] 
    public int year { set; get; } 
    [Required] 
    public int axNodes { set; get; } 
    [Required] 
    [Range(1, 2, ErrorMessage="Survived = 1; Did not survive = 2")] 
    public int survival { set; get; } 

    public string answer { set; get; } 

    public void generatePrediction() 
    { 
     StreamWriter i = new StreamWriter(@"input.arff"); 
     i.WriteLine(@"relation haberman\n\n@attribute  Age_of_patient_at_time_of_operation INTEGER\n@attribute Patients_year_of_operation {58,59,60,61,62,63,64,65,66,67,68,69}\n@attribute Number_of_positive_axillary_nodes_detected INTEGER\n@attribute Survival_status {1,2}\n\n@data"); 
     i.WriteLine(age + "," + year + "," + axNodes + "," + survival); 
     i.Close(); 
     Process genPrediction = new Process(); 
     genPrediction.StartInfo = new ProcessStartInfo() 
     { 
      CreateNoWindow = true, 
      FileName = @"habermanCommand.bat", 
      WindowStyle = ProcessWindowStyle.Hidden, 
      Arguments = "cmd.exe" 
     }; 
     genPrediction.Start(); 
     genPrediction.WaitForExit(); 
     genPrediction.Dispose(); 

     StreamReader readPrediction = new StreamReader(@"output.txt"); 
     string line = readPrediction.ReadLine(); 
     while (line != null) 
     { 
     if (line.Contains(':')) 
     { 
      string[] part = line.Split(':'); 
      if (part[2].Contains('+')) 
      { 
       string[] prediction = part[2].Split('+'); 
       if (part[2][0] == '1') 
        answer = "\t(Survived)\t\tProbability that your assessment was incorrect:\t" + (Convert.ToDecimal(prediction[1].Trim()) * 100) + "%"; 
       else answer = "\t(Did not Survive)\tProbability that your assessment was incorrect:\t" + (Convert.ToDecimal(prediction[1].Trim()) * 100) + "%"; 
      } 
      else 
      { 
       string line1 = ""; 
       string lineTrimmed = ""; 
       for (int j = 1; j < part[2].Length; j++) 
        line1 += part[2][j]; 
       for (int l = 0; l < line1.Length; l++) 
        if (line1[l] != ' ') 
         lineTrimmed += line1[l]; 
       if (part[2][0] == '1') 
        answer = "\t(Survived)\t\tProbability that your assessment was correct:\t" + (Convert.ToDecimal(lineTrimmed) * 100) + "%"; 
       else 
        answer = "\t(Did not Survive)\tProbability that your assessment was correct:\t" + (Convert.ToDecimal(lineTrimmed) * 100) + "%"; 
      } 
      } 
      line = readPrediction.ReadLine(); 
     } 
     readPrediction.Close(); 
    } 

} 
} 

控制器指定兩個觀點，即在它們之間的數據流應：

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Web; 
using System.Web.Mvc; 
using MvcHaberman.Models; 
using DataAnnotationsExtensions; 

namespace MvcHaberman.Controllers 
{ 
public class HabermanController : Controller 
{ 
    public ActionResult Index() 
    { 
     HabermanPrediction obj = new HabermanPrediction(); 

     if (ModelState.IsValid == false) 
     { 
      return Redirect("/Habberman/Index"); 
     } 
     else return View(obj); 
    } 

    public ActionResult About() 
    { 
     return View(); 
    } 

    public ActionResult DisplayPrediction(HabermanPrediction objOut) 
    { 
     objOut.generatePrediction(); 
     return View(objOut); 
    } 
} 
} 

提交視圖：

@model MvcHaberman.Models.HabermanPrediction 
@using (Html.BeginForm()) { 
@Html.ValidationSummary(true) 
<fieldset> 
    <legend>HabermanPrediction</legend> 

    <div class="editor-label"> 
     @Html.LabelFor(model => model.age) 

    </div> 
    <div class="editor-field"> 
     @Html.EditorFor(model => model.age) 
     @Html.ValidationMessageFor(model => model.age) 
    </div> 

    <div class="editor-label"> 
     @Html.LabelFor(model => model.year) 
    </div> 
    <div class="editor-field" > 
     @Html.EditorFor(model => model.year) 
     @Html.ValidationMessageFor(model => model.year) 
    </div> 

    <div class="editor-label"> 
     @Html.LabelFor(model => model.axNodes) 
    </div> 
    <div class="editor-field" > 
     @Html.EditorFor(model => model.axNodes) 
     @Html.ValidationMessageFor(model => model.axNodes) 
    </div> 

    <div class="editor-label"> 
     @Html.LabelFor(model => model.survival) 
    </div> 
    <div class="editor-field" > 
     @Html.EditorFor(model => model.survival) 
     @Html.ValidationMessageFor(model => model.survival) 
    </div> 
    <p> 
     @Html.ActionLink("Generate Prediction", "DisplayPrediction") 

    </p> 
</fieldset> 
} 

輸出視圖：

`@model MvcHaberman.Models.HabermanPrediction` 
`@using MvcHaberman.Models` 
<!DOCTYPE html> 
<html> 
<head> 
    <title>DisplayPrediction</title> 
</head> 
@using (Html.BeginForm()) 
{ 
<body> 
<div class= "label"> 
@Html.LabelFor(model => model.answer) 
</div> 
<div> 
    <h1>@Model.age</h1> 
    <h2>@Model.answer</h2> 
</div> 
</body> 
} 
</html> 

Answer 1

當您使用View（OBJ）方法，它會生成一個名爲OBJ默認模式的新景觀。所以當頁面刷新時，html元素的默認值設置爲你的模型參數（在這個場景中是obj參數）。