ASP.NET MVC3应用程序中的简单DropDownList

Question

我需要在表单中使用简单的DropDownList,我不想创建像ViewModel这样的东西.我在关系1中有两个模型(表):n:

public class Course
{
    public int ID { get; set; }
    public string Name { get; set; }
}

和

public class Project
{
    public int ID { get; set; }
    public int CourseId { get; set; }
    public int ProjectNo { get; set; }
    public string Name { get; set; }
    public DateTime Deadline { get; set; }
}

在"创建项目"中,我想从课程表(模型)中获取带有Id(作为值)和名称(作为文本)的DropDownList.在新项目中将插入选择的CourseId.我怎么能这么简单呢？

Answer 1

您不想使用ViewModel的任何特殊原因？他们对这类问题非常有帮助.

如果您不想使用ViewModel,那么您可以在控制器中构造一个特定的类,它是两个类所需的属性的集合:

public ActionResult Show(int id)
{
    Course course = repository.GetCourse(id); // whatever your persistence logic is here
    Project project = projectRepository.GetProjectByCourseId(id);
    string CourseName = from c in course where
                            c.ID == project.courseID
                            select c.Name;
    IEnumerable<SelectListItem> selectList = 
    from c in course
    select new SelectListItem
    {
        Selected = (c.ID == project.CourseId),
        Text = c.Name,
        Value = project.CourseId.ToString()
    };
    //add the selectList to your model here.
    return View(); //add the model to your view and return it.
}

为此设置ViewModel会容易得多,因此您可以拥有强类型视图.让我演示给你看:

public class ProjectCourseViewModel
{
    public SelectList ProjectCourseList {get; private set; }
    public Project Project {get; private set; }
    public Course Course {get; private set; }

    public ProjectCourseViewModel(Project project, Course course)
    {
        ProjectCourseList = GetProjectCourseSelectList(project, course)
        Project = project;
        Course = course;
    }

    private SelectList GetProjectCourseSelectList(Project project, Course course)
    {
        IEnumerable<SelectListItem> selectList = 
        from c in course
        select new SelectListItem
        {
            Selected = (c.ID == project.CourseId),
            Text = c.Name,
            Value = project.CourseId.ToString()
        };
    }

}

然后你的控制器会非常简单:

public ActionResult Show(int id)
{
    Course course = repository.GetCourse(id);
    Project project = projectRepository.GetProjectByCourseId(id);
    ProjectCourseViewModel pcvm = new ProjectCourseViewModel(project, course)
    return View(pcvm); 
}

然后你的视图采用强类型模型,你不必依赖ViewData,这是一件好事.

注意:我没有编译它,只是编写它.可能存在编译错误.