如何从ASP.NET MVC中的视图到控制器中动态添加值？ [英] How to receive dynamically added values from view to controller in ASP.NET MVC?

问题描述

我在asp.net mvc中学习一些概念。我正在使用实体框架和visual studio 2013社区版。我正在创建一个用于学习的演示程序。我已经根据

加号按钮有一个脚本，来自我早期的问题

为什么会发生这种情况？
PS：我可能会忽略实时场景，因为这是用于学习和清除与实体框架的一对多关系的概念以及使用MVC的演示应用程序。

解决方案

这个为我工作。只需更改脚本中的名称，并在httppost中添加字符串数组。

I am learning some concepts in asp.net mvc. I am using entity framework and visual studio 2013 community edition. I am creating a demo app for learning. I have created model according to this link. The models are as follows. Below is course model. The course has department as foreign key. A department can have many courses.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

namespace ManyItemsDemo2.Models
{  
    public class Course
    {
        public int CourseID { get; set; }
        public string Title { get; set; }
        public string Credits { get; set; }
        public int DepartmentID { get; set; }

        public virtual Department Department { get; set; }
    }
}

This is department model. The department model is simple. It is associated with course model.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

namespace ManyItemsDemo2.Models
{
    public class Department
    {
        public Department()
        {
            this.Cources = new HashSet<Course>();
        }
        public int DepartmentID { get; set; }
        public string Name { get; set; }
        public double Budget { get; set; }
        public string Administrator { get; set; }

        public virtual ICollection<Course> Cources { get; set; }
    }
}

There is a context class.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data.Entity;

namespace ManyItemsDemo2.Models
{
    public class SchoolContext:DbContext
    {
        public SchoolContext() : base("SchoolContext") { }

        public DbSet<Course> Courses { get; set; }
        public DbSet<Department> Departments { get; set; }
    }
}

Now i have used scafolding and created controllers and views with CRUD functionality. I can create a department and courses in views. Now i need to assign multiple courses while creation of departments. So i created a this view model. Here One department has many courses.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using ManyItemsDemo2.Models;

namespace ManyItemsDemo2.ViewModels
{
    public class DeptCourses
    {
        public Department Department { get; set; }
        public IEnumerable<Course> Course { get; set; }
    }

}

along with this i created a new view. Which can accept more cources while creating department. The view result is like this.

The plus button has a script which is from my earlier question here. The script uses jquery and clones the drop down and adds back.

The problem starts from here. When i add more than one drop down, let say 3, i am receiving null in controller, though i receives three elements, only one element has value, others are null. See the image for more clarification.

Why this happens? PS: I might overlooked real time scenarios as this is demo app for learning and clearing the concepts of one to many relationships with entity framework along with using MVC.

解决方案

This worked for me. Just changed the name in script and added string array in httppost.

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